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PR I M E R 




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Scientific Soil Culture Series 



RICHARD A. HASTE, Editor 



Manual of Soil Culture Cam phe 1 1 
Soil Culture Primer — Campbell 
Whesit— Ten Eyck 

IN PREPARATION 
The Soil— ffl /lard 

Plant Growth — Haste 

Soil Tillage— Crtw/)/;^'// 

Soil Biology— -Bo/M' 

Orchard and Small Fruits Stephens 

Plant Breeding^5«/Mw 

Irrigation and Drainage — Haste 

Manual of Soil Culture, two volumes — Campbell 

Farm Management — Haste 



Campbell Soil Culture Publishing Co, 

Lincoln, Nebraska 



WUUIMHI[»nHIUtlllt)(MMIWItO«Ml««tWUl(mniTBMOnBllffliroiTIIIIIII MKfflW W W 




HARDY W. CAMPBELL 



Soil Culture Primer 



A plain and practical discussion of the relation of plants to the soil and 

the principles of growth; the laws governing the movement of water 

in the soil and its evaporation from the surface, and the principles 

of the conservation of soil moisture by cultivation, together with 

a full description of the practice of scientific soil culture 

known as the Campbell System, for the use of students 

and practical : farmers everywhere but especially 

in the semi-arid regions of the world 



HARDY WrCAMPBELL 

Author of Camp))eirs Manual of Soil Culture 



REVISED AND EDITED 
BY 

RICHARD A. HASTE 

Editor of Campbell's Scientific Farmer 



COPYRIGHTED 1914 



LINCOLN, NEBRASKA 

CAMPBELL SOIL CULTURE PUB. CO. 

1914 



SBiio 

,C3 



CONTENTS 



Introduction 

How to Use This Text . 

The Semi-Arid Belt 

Plants and Their Structure . 

Soil Moisture 

Objects of Cultivation 

Purposes of Scientific Tillage 

Packing and Packers . 

Cultivation .... 

The Soil Mulch . 

Summer Tillage . 

Storage of Moisture 

Conservation of Moisture 

Physical Condition of the Soil 

The Disk Harrow 

Saving Water by Cultivation 

Corn 

Wheat . 

Irrigation 

Crop Rotation 

Necessary Farm Tools 

©JU380340 



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L 



^ INTRODUCTION 
a^ 

v' It is with great pleasure that we offer to the public the 

fourth edition of Campbell's first manual of soil culture. 
This little book, which was first published in 1905, has been 
read wherever the English language is spoken. Moreover, it 
has been translated into Russian, German, and Hungarian, 
and the principles of soil tillage here for the first time arranged 
into a logical system are now taught in the agricultural schools 
and colleges of every civilized nation on the globe. The 
Campbell system of soil tillage as outlined in this manual, has 
doubled the agricultural area of the world. It is the key that 
has unlocked the storehouse of the great plains country of 
North America. The appearance of this little volume marked 
the beginning of the great dry farming movement that has 
spread the knowledge of scientific soil culture to every quarter 
of the globe. 

It is with great satisfaction, therefore, that we have re- 
arranged the topics of the third edition, illuminating them 
with the light of experience gained in the last ten years, both 
in this and in foreign countries. Within the limits of this 
book we can present only the elementary principles involved 
in scientific soil tillage (a full exposition of scientific soil culture 
and crop growing being found in the 1914 edition of the large 
manual), but we trust it will serve as a guide-board pointing 
the way to better methods, larger yields, and happier homes. 

It is not intended to lay down a code of imperative rules 
to govern the farmer in every act of soil tillage, but to present 
the fundamental principles governing the development of 
plant life, the movement of water in the soil, the release of 
potential fertility, and the effect of proper tillage on the quality 
and quantity of the crops. When these fundamental principles 
have been thoroughly mastered the labor necessary to aid the 
crop in its development and render agriculture profitable will 
become evident to any one who is able to trace out cause and 
effect. 

The farmer who works by rule, not knowing the principles 
involved, will fail as often as he succeeds. With him farming 
is a game of dice. He has no idea what the next throw will 
turn up. But, knowing the principles, he uses his judgment 
and varies his action with the changing conditions. If the 



6 CampheW slSoillCulture Primer 

soil is too wet it must be drained, but if on account of in- 
sufficient rainfall it is too dry, the moisture must be conserved 
by proper preparation of the seed and root beds, and after 
cultivation for the benefit of the plant. We have learned how 
much moisture is required to produce a pound of dry matter 
of the various field crops; we have also learned how to hold 
the rainfall in the soil. Crop growing in the semi-arid regions 
then becomes a problem of the application of our knowledge to 
the conditions that we find. We cannot grow crops without 
water. This water must be supplied by either natural rainfall 
or by artificial irrigation. If the precipitation in the form 
"of rain and snow averages eighteen inches per annum, and the 
evaporation is not excessive, field crops can be produced if 
the proper means are employed to catch and hold this moisture 
in the soil. This has been demonstrated so many times that 
it is no longer questioned by the intelligent investigator. 

If the methods laid down in this manual for the conserva- 
tion of soil moisture are carefully followed by the farmers in 
the great semi-arid regions of the United States and Canada, 
where the annual precipitation averages more than fourteen 
inches, cereals and the ordinary fodder crops can be produced 
profitably, and with reasonable certainty. 

The storage and conservation of soil moisture by the 
careful preparation and tillage of the soil is the basis of all 
fruitful production. We have all observed the improved con- 
dition of the winter wheat where, owing to some obstruction 
in the field, snow drifts have lodged. The old idea was that 
the snow drift had acted like a blanket to protect the wheat 
during the winter and that the larger stand and better yield 
on that particular spot was owing to this protection. This 
we now understand was an error. The improved stand of 
grain was due to the fact that the hard-packed snow melted 
slowly and the moisture percolated into the soil to a much 
greater depth than in the exposed portions of the field and was 
stored there as in a reservoir for the use of the growing crop, 
so that when the summer drouths came and the wheat in the 
general field was checked in its growth by a scarcity of moisture, 
the stored moisture beneath the snow drift supplied the roots 
and kept the plants vigorous and growing. The roots of the 
plants, growing on the spot where the snow had drifted, were 
supplied from the reservoir of moisture below, which had 
come down into the lower strata of the soil as the snow melted 
in the spring, and was now slowly raised to the roots of the 
plants by the force of capillarity. 



Ca7npbell's Soil Culture Primer 7 

Similar results are observed when spring crops are planted 
on soil which has been covered with snow drifts that have 
slowly melted in the spring, the water sinking into the soil. 
It follows from these simple observations that the greater 
amount of water we can store in the soil before planting the 
crop and during its growth, the greater will be the yield, 
providing we so cultivate the surface as to prevent evaporation 
and thus hold the moisture for the use of the plant. 

Another feature of scientific soil tillage, next in importance 
to the conservation of moisture, is the physical condition of the 
root bed. This should be fine and firm, that it may hold the 
moisture necessary to a vigorous root growth, for without a 
strong root system no plant can resist the periodical drouths 
that are bound to come. 

And right here let us impress upon the reader, if by 
chance he is interested in irrigation, that all the principles 
herein outlined, having reference to the physical condition 
of the soil, the conservation of water, and the relation they 
sustain to plant life, apply with equal force to crop growing 
under irrigation. Dry farming is only a name to distinguish 
farming under natural rainfall from farming under a ditch — 
the principles involved in both cases are the same. 

With these considerations in mind we have tried in the 
following pages to give a clear and succinct statement of the 
principles involved in all operations of soil tillage, having for 
their object the production of crops in both the humid and 
semi-arid sections of the world. Naturally these exact methods 
are more essential for success in the arid and semi-arid sections 
where the conservation of moisture is the primal consideration 
and crops cannot be grown without them, but they also apply 
to the regions of plentiful rainfall where drainage is necessary 
and drouths are likely to come. 




Campbell's Soil Culture Priyner 



HOW TO USE THIS TEXT 

Do not get the idea that you can read this manual and 
then put into immediate practice the principles of scientific 
soil culture. If you do, you will be disappointed. Our com- 
mon law is based on the principles of equity, justice, and 
common sense. Yet the best lawyers must study for years 
before they are able to reason out the right from the mass of 
complicated evidence and conditions that come up with 
every new case. The physician gives years of study to the 
science of medicine and yet so complicated are the conditions 
that he is often puzzled to know just which principle to apply. 
The same is true of the application of the principles of soil 
tillage to the varied conditions that are constantly arising. 
No two sets of conditions are alike and the application of the 
basic principles must be a matter of judgment. The reader 
will find it necessary, therefore, to go over and over the con- 
tents of this little book until he has mastered the principles 
and is able to apply them with judgment to the conditions 
as he finds them. 

The cook in the kitchen may fail the first time she uses a 
new recipe. She has followed the directions in the cook book 
but somehow the result is not satisfactory. She tries again 
with better results and a third time with success. Uncon- 
sciously she has used her judgment and modified the directions 
to suit the conditions. She has not only studied the cook 
book but she has studied the ingredients and noted the tem- 
perature of the oven and the hundred other little things that 
affect results in the kitchen. 

When you have read this book once, read it again — 
study it as you would a text book in school. Note what is 
said and compare it with your own experience and what 
others have written and said. Get the principles in mind, and 
then see to it that you are able to reason from these principles 
to the conditions that you have to meet. If you know why 
wheat should be rolled or harrowed in the spring, you will be 
able to determine from the condition of your field whether 
it needs harrowing or rolling, and when. The essential thing 
is to so understand the soil in its relation to moisture and 
plant life as to be able to reason fully and accurately what 
the effect of certain conditions will be, just when and how 
certain work should be done, and what results may be reason- 
ably expected. 



Campbell's Soil Culture Primer 9 

CHAPTER 1 

THE SEMI-ARID BELT 

A line drawn from the western lobe of the Lake of the 
Woods to Galveston, Texas, along the ninety-fifth meridian, 
will divide the United States into two nearly equal sections, 
and will mark in a general way the dividing line between the 
wooded and the treeless regions. This line is not regular, in 
fact there is a neutral ground of interspersed prairie and wood- 
land that occupies the immediate valley of the Mississippi 
and Missouri. The history of the settlement of this middle 
ground by the pioneers from the east is an old story. Being 
used to the timber of New England and the eastern middle 
states they clung to the woods and avoided the prairies of 
Illinois and Iowa, thinking that the soil was worthless because 
it would not gi'ow trees. It took twenty years to overcome 
this prejudice and induce them to brave the unknown dangers 
of the rich prairies. It was about 1875, when, encouraged by 
their success with the prairies, the bolder pioneers crossed the 
ninety-eighth meridian and entered the great plains — the 
Great American Desert as the old geographers called it. By 
thousands they flocked into the Dakotas and Nebraska and 
Kansas. A few favorable years encouraged them. Someone 
said that the rainfall followed the plow and everyone was 
ready to believe it. For a number of years this theory seemed 
to be the true one, and then came the great drouths and the 
return tide set in. A few stayed, and with the aid of their 
cows and chickens held the fort during the years of drouth 
and famine until the return of the rains and the new tide of 
immigration. Like the pioneers of Iowa they are wealthy 
now. In the early nineties the tide was turned back again, 
only to be renewed five years later. Each time the frontier 
was pushed farther west — the desert receding before the 
increasing knowledge of the soil and its possibilities. 

Up to 1894 little attention had been given to the new 
problems of the soil. Old methods, such as were used in 
Illinois and Iowa were employed and when failure followed 
it was laid to a lack of timely rainfall. The question of the 
conservation of the moisture by tillage had not occurred to 
them. Great schemes were put on foot to overcome the 
disasters of the drouth. The press drill and other special 
tools of soil culture were introduced to overcome the lack of 
rainfall. Summer fallow was tried without effect. The ' 'rain- 



10 Campbell's Soil Culture Primer 

maker" came with boastful confidence in the power of ex- 
plosives to produce rain, and failed. 

Then someone said that the presence of trees would bring 
rain, so thousands of acres of trees were planted, with the 
encouragement of the government through the tree claim act, 
only to be withered by hot winds or slowly dried out by long 
summer drouths. 

Agricultural colleges and experiment stations were estab- 
lished at various points in the semi-arid belt, but the problems 
were new and the experiments were directed toward finding 
drouth resistant crops rather than to finding ways and means 
to conserve and utilize the moisture that God was giving every 
year and which under the old methods was allowed to go to 
waste. 

It was not until the conservation and storage of the 
natural rainfall in the soil began to be comprehended, that 
there was any real light thrown on the problems of the great 
semi-arid belt. 

The experience of the writer in South Dakota in the 
eighties, suggested this solution which time has fully proved 
to be the only means of placing the semi-arid regions of the 
world in the agricultural columns where nature evidently 
intended it should be. 

As we more fully comprehend the forces of nature we 
become the more convinced that there is a law of compensation; 
that if we only seek diligently and with an open mind we will 
discover that everything has its use. It is within the bounds of 
possibility that the one time American desert before many 
years will become the center of the greatest agricultural region 
of the world. It is to assist those who are trying to solve the 
problems of scientific soil tillage in the semi-arid regions of 
the world that the following pages embodying the experience 
of the last thirty years have been written and given to the 
world. 



CampheU's Soil Culture Primer 11 

CHAPTER 2 
PLANTS AND THEIR STRUCTURE 

Plants Resemble Animals 

In order to fully understand the principles of soil tillage 
it is necessary to know something about the structure and 
habits of plants and their relation to the soil. As this is but 
a primer and deals with first principles only we shall be brief, 
but we hope the reader will study the following carefully, 
because it is one of the essential links in the chain. 

Plants resemble animals in both the structure and the 
functions of their essential organs. Animals eat, drink and 
breathe. So do plants. Deprive an animal of water, food 
or air, and it will die — so will the plant. They both require 
the same food elements, but of course in different form. They 
both start life from a division of cells and develop by a mul- 
tiplication of cells. The chief outward difference is that 
plants are attached to the earth and animals move about 
freely. The plant, however, in compensation has an advantage 
over the animal in the fact that it can manufacture its food 
from the original elements of the earth, while the animal must 
have this food prepared by some outside agency. 
The Miracle of Growth 

This food factory in each plant is very interesting and as 
an understanding of it lies at the very base of scientific agri- 
culture, we will try to learn how it is operated and under 
what conditions the best results are obtained. The value of 
a cultivated plant is measured by its ability to gather food 
from the soil and from this raw material manufacture grain 
or fruit. 

To take dead forms and change them into living things, 
once would have been regarded as a miracle. But that 
miracle is being performed by millions of plants every hour 
of the day — all over the world. It is the miracle of growth. 
To help the plant in the performance of this wonder-miracle 
by intelligent cultivation is the duty of every farmer. 
Origin of Life 

We do not know what life is — we know only its manifesta- 
tions. But we do know when things are alive and when they 
are dead. As a general rule, things that are alive grow. 
A quartz crystal, if kept from the weather, is the same yester- 
day, today and tomorrow. It is dead. But a living thing 
changes from day to day, or from year to year. It cannot 
remain the same — it has life. 



12 Camphell's Soil Culture Primer 

Plants, from the microscopic bacteria that form the green 
scum of the stagnant pool, or the mould on stale bread, to the 
oak tree are all composed of cells — microscopic cells, the walls 
of which are composed of cellulose — a non-living substance, 
but within is a jelly-like matter called protoplasm. 
Chromatin 

Within these protoplasmic cells is a microscopic body 
in the shape of a sphere called the nucleus — this nucleus con- 
tains a substance called chromatin. This is as near the origin 
of life as science has been able to get. The protoplasmic cells 
have the power to build new cells from the lifeless material 
about them. Protoplasm has the power of independent move- 
ment, and is able through some chemical action, to tear down 
and build up cell structures. As long as these chemical 
processes go on, protoplasm is alive — when they cease, it is 
dead. 

Protoplasm has the power of increasing, or growing, by 
a division of its cells. When this takes place the nucleus 
divides, pulling apart, forming two separate and complete 
cells, which in their turn divide. This is the lowest form of 
growth. The entire structure of plants, from the roots to the 
leaves and flowers, is but a repetition of this cell formation. 
A tree grows simply by adding additional cells to its stem and 
branches. 
Elements Essential to Plant Growth 

The elements that are used in the plant laboratory for 
the manufacture of its food are very many. But those regarded 
as essential to plant growth are oxygen, nitrogen, hydrogen, 
potassium, calcium, magnesium, chlorine, phosphorus, iron and 
sulphur. With the exception of oxygen all these elements are 
absorbed by the plant in some kind of chemical compound, 
such as carbonic acid, nitrates, carbonates, sulphates and 
water. Now this may sound very technical and difficult to 
remember, but it is all very simple. 

The chief constituent of all plant substances is carbon. 
It forms fully one-half of the total weight of dry vegetable 
matter. The great coal deposits of the world are mostly 
carbon. Charcoal is the wood of a tree with the other elements 
driven off by heat, leaving the carbon. And this carbon is 
obtained almost wholly from the air, while in the form of 
carbonic acid gas — a combination of carbon and oxygen. We 
shall see later that this gas laden with its carbon, is taken into 
the laboratory of the plant through the leaves. A small 
amount of carbon, however, is brought in through the roots 
in water solution. 



CampheU's Soil Culture Primer 13 

Roots as Food Gatherers 

The other elements are found free in the soil or in various 
combinations, and it is the business of the roots to go out and 
gather them in. But the plant can not use them nor transport 
them unless they are dissolved in water. Water, then is as 
essential to the life and growth of a plant as is food — in fact 
it is the only means by which food can be taken into or utilized 
by the plant, and this water can reach the interior of the 
plant only through the roots. 

The roots, therefore, are not only the food providers of 
the plant, but they are the water carriers as well. They are 
the field men that go out and gather in the raw material 
which is needed by the plant food factory. They not only 
gather and select it, but they build little canals and supply 
water transportation for whatever is needed. The manner in 
which the roots do these things is most interesting and most 
important, and the man who does not know something of the 
functions and habits of roots — how they do their work — ^is not 
prepared to intelligently cultivate his crops. 

Structure and Functions 

There is no particular difference between the structure of 
roots and the structure of branches and leaves. They are all 
formed by a multiplication of cells and they grow by adding 
cell after cell to the tips. From the main root a number of 
small branches are put out which give rise to other branches, 
pushing their way between the soil particles, seeking for air 
and moisture containing the food desired by the parent plant. 
Covering the smallest rootlets are millions of microscopic 
hairs — little cellular filaments, which have the power to absorb 
from the soil-particles the moisture that holds in solution the 
various chemical elements wanted. 

Soil Moisture 

Soil moisture is of three kinds — free, capillary and hy- 
groscopic. The free water is that which percolates, or runs 
between the particles of soil causing it to become wet and 
slushy. This is the water that disappears when the soil is 
well drained. Capillary moisture is that which remains in 
the soil and gives it the feeling of dampness. Capillary 
moisture moves freely among the soil particles and always in 
the direction of the dryer portions. When the surface becomes 
dry by evaporation, the capillary water moves up from below 
to equalize the water content of the soil. Capillary moisture 
is held by the attraction of the soil-particles for the molecules 



14 



CampheU's Soil Culture Primer 



of water. It is the capillary water that the plant mainly 
depends on for its growth. 

In the air around each microscopic particle of soil is a 
small amount of moisture held so firmly in place that it is 
influenced neither by gravity nor by capillarity. This is 
called hygroscopic moisture and is present in all soils, but it 
is of no immediate use to the plant. 
Office of Root Hairs 

Now coming back to the thread-like filaments called root 
hairs, we find that they attach themselves to the soil particles 
and absorb soil moisture into their cells. When the film 
about one soil-particle is exhausted moisture flows in from 
another particle under a law of equilibrium. This moisture 
charged with the elements of plant food is passed along the 
cells of the root hairs to the larger roots and so on to the stem 
of the plant. 

The growing rootlets, and root hairs are absorbent for 




Fig. I 

Root Hairs and Soil Particles Greatly Magnified. The Dark Spaces 

Represent Soil Particles, the Shaded Portion Moisture, and 

the Light Spots Air 



Campbell's Soil Culture Primer 



15 



water with mineral matter in solution only at their tips for 
probably not more than one- tenth of an inch. As they grow 
the body of the root, back from the tip, becomes covered with 
a layer of cork cells, full of air, which prevents the entrance^of 
water. So it will be seen that the active part of the root 
today becomes inactive tomorrow, and that fresh mouths are 
continuously opening eager for food. This is why it is useless 
to water a tree or a plant close to its base — the feeding roots 
are apt to be far distant. 




Fig. II 

Cross Section of a Root Magnified Showing Root Hairs Attached 
to Particles of Soil, h — Root Hairs on a Primary Root 



You see how important it is to know the root habits of 
plants that you are cultivating. If you are irrigating, you 
will know where the plant wants water, and if you are cultivat- 
ing you may avoid disturbing the food-gatherers as they are 
wandering around beneath the surface. 
Air in Soil 

As the process of root growing is nothing more than the 
adding and breaking up of cells of protoplasm, they must have 
access to the oxygen of the air in order to complete the chemical 
change necessary to this gi'owth and decay. If the soil has 
not a certain amount of air in it, root growth will stop. That 



16 Campbell's Soil Culture Primer 

is why plants are said to drown out and fruit trees are said to 
get wet feet. The ground becomes so saturated with water, 
that all air is excluded, and the roots suffocate for want of 
oxygen. This fact is very closely related with tillage. You 
will find hereafter, that a crust is liable to form under the 
mulch in well-tilled corn fields, completely shutting out the 
air from the roots, causing the corn to curl and show all the 
signs of a lack of water, although there is plenty of moisture 
in the soil below the crust. The air has been shut off by the 
formation of the crust and the roots stop work. 

Air and Its Importance in the Soil 

Air in the soil has not received the attention and study 
that its importance demands. 

Because we have seen it constantly demonstrated we know 
the necessity of water in the soil for plant growth, but it is 
not so easy to comprehend the material value to the plant of 
air in the soil. We cannot see its effect in anything like as 
broad a sense as we do the water, yet this presence in proper 
quantities in the soil and about the roots of the plants is just 
as vital to its life, health and growth as water. 

Water without air and its component parts is worthless; 
air without water and its component parts is equally valueless 
to the growth and development of all farm crops. 

How many times have we seen a field of wheat, corn or 
oats, possibly half-grown, and noted that in some depression 
the crop was ranker in growth and also a darker green. If a 
rain of considerable magnitude comes and the depression fills 
with water and remains there for some days, the plants that 
seemed to have the advantage before the rain now begin to 
lose their healthy green; if the water remains long enough 
over the surface they turn yellow, then brown, and finally 
die. This is because of a lack of air at the roots. 

Osmosis 

All plants have the power of taking in through the cells 
of their root tips and their root hairs, the substances necessary 
to their growth. This process of absorbing soil moisture is 
called osmosis. Just why the absorbent cells will take in 
certain substances and reject others is not known. Goff 
explains it by citing the law of diffusion, and Widtsoe 
explains it substantially as follows: When the solution of 
water within the plant is stronger than that of the soil water 
the effort to equalize it causes the solution to flow from the 
soil to the plant. But whenever the solution in the soil be- 



Campbell's Soil Culture Primer 



17 



comes stronger than that of the plant, the process not only 
ceases, but is reversed. This is why soils heavily impregnated 
with alkali become fatal to plant life. 

The Leaves 

Leaves are popularly believed to be the lungs of the 
plant. While this is in a sense true, they are more like the 
digestive organs, for they are in every sense the food factories 
of the plant. It is here that the original elements taken from 
the soil and from the air are broken up and recombined into 
forms that may be turned into tissue. 






Wi 


w 


/ 












' ■-■ _;^ 



MEMBRA.'JE- 




Fig. Ill 

A Common Experiment Showing the Similarity of the Action of 
Osmosis in Plants and a Salt Solution Through a Membrane 

Chlorophyll 

When a leaf is exposed to light it turns green. This green 
color is due to a substance known as chlorophyll. This chloro- 
phyll is produced in some mysterious way by the action of 
sunlight on protoplasm. That it is produced by the immediate 
action of sunlight is proven by the fact that it disappears 



18 CampheU's Soil Culture Primer 

whenever the plant or the leaf is removed from the light of 
the sun. The bleaching of celery is simply the removal of 
chlorophyll. The pale and sickly color of potato sprouts in 
the cellar is due to the absence of chlorophyll. 

Chlorophyll forms in minute globules which adhere to 
the cell walls. They are more numerous near the upper surface 
of the leaf where the sunlight is stronger. The function of 
chlorophyll, or the work that it performs in the food factory 
must be borne in mind in all our study of plant life, for without 
it the plant has no power of assimilation — no povv-er to form 
plant food from the raw ingredients of the soil and air. Chloro- 
phyll and sunlight are the two magicians that take the dead 
particles of earth and transform them into food for living 
cells. 

What Happens in the Leaf 

If you heat starch it will separate into water and carbon 
dioxide. This suggests that it can be formed by the union of 
water and carbon dioxide, and this is just what is brought 
about by the action of sunlight in the leaf. The leaf absorbs 
carbon dioxide from the air and by utilizing the energy of the 
sun to break up the combination between the carbon and 
oxygen, it liberates the carbon, which immediately unites with 
the water which has been drawn up from the roots, forming 
starch. The oxygen not being needed, is allowed to pass off 
into the air. The leaf, therefore, becomes a starch factory 
and starch is the original food of all plants. In order to run 
this factory to its greatest capacity, the leaf exposes its greatest 
surface to the sun's rays, but in so doing it runs the risk of 
losing too much water by evaporation. 

Stomata or Leaf Pores 

An arrangement, therefore, is made for numerous openings 
mostly on the under side of the leaf, called stomata, through 
which the oxygen that has been liberated by the decomposition 
of the carbon dioxide and water is allowed to escape. When 
there is an abundance of moisture in the ground at the disposal 
of the plant, these little valves are open, allowing a large 
per cent of moisture to escape, but when the moisture in the 
ground is limited these valves automatically close, thus 
preventing unnecessary escapement of moisture. This process 
of absorption by the roots and evaporation from the leaves is 
called transpiration, and much depends upon a correct under- 
standing of the principles governing it and the means by 
which it may be controlled, for like the respiration of a human 



Camphell'sSoil Culture Primer 



19 



being the transpiration of the plant indicates very clearly its 
physical condition. 

The action of these little guard cells in the stomata is 
very curious. They close at night and mostly on cloudy days. 
This makes it possible to fumigate orchards with poisonous 
vapors at night which would be fatal to the plants if done in 
the day time. Also it will be observed that these openings 
are carefully guarded by being mostly on the under side of 
the leaf and surrounded by waterproof material. This is why 
a leaf glistens with a multitude of little points when immersed 
in water. 

The exact chemical process which takes place in the leaf 
cells is described in the Encyclopedia of American Agriculture 
as follows: 

Carbon dioxide passes through the stomata, comes thor- 
oughly into contact with the leaf cells which are sufficiently 
separated from each other to allow it to pass unavoidably 
between them. The great absorptive surface which they 
expose is kept continuously moist and is thus able to absorb 
with great rapidity much as the moisture along the surface 
absorbs the oxygen. The exposed carbon dioxide passes into 
the cell and comes into contact with the green chlorophyll 
grains. The chlorophyll in these portions is divided into very 
minute drops — thus giving it an enormous absorptive surface. 
At the same time that it takes up carbon dioxide it absorbs 
sunlight and with energy thus received it decomposes the 
carbon dioxide, causing the carbon to unite with the water, 
thus forming sugar. This may be illustrated by the equation 
6C0,+ 6H,0= C«H,,0«+ 6O2 

Carbon dioxide Water Grape Sugar Oxygen. 




20 Campbell's Soil Culture Primer 

CHAPTER 3 
SOIL MOISTURE 

Movement of Soil Moisture 

Water is the life blood of plants. Nothing will grow or 
even germinate without moisture. It is very clear then that 
on the presence of moisture and its movement in the soil 
depends not only the life of the plant but the yield of all farm 
crops. You see how important it is for the farmer to under- 
stand how this water moves in the soil and how best to store 
it for the use of the plant. 

We learned in the previous chapter that soil moisture 
was of three kinds — gravitational, capillary and hygroscopic; 
that gravitational water is the free water of the soil — the 
water that seeps down through the soil and drains off into the 
streams and lakes — that capillary water is that which surrounds 
each particle of soil and is held there by the force of capillary 
attraction; that hygroscopic water is that which is to be found 
in the air of the soil, filling the spaces between the soil particles. 
It is important to know here that neither the gravitational 
water nor the hygroscopic water is of any use to field crops 
directly. It is only the capillary water in contact with the 
roots that furnishes the plant with food. There are some 
exceptions to this rule but it is sufficiently accurate to answer 
our present purpose. 

Capillarity in the Soil 

We all know that if we put one end of a towel in a bowl 
of water the water somehow will find its way to the other end 
of the towel. We know that a sponge will take up or absorb 
water from a dish as soon as one part of it touches the surface. 
We know that the oil in a lamp, in some way, climbs up the 
wick to the flame where it is burned. We know, too, that 
blotting paper will absorb ink. In all these familiar cases we 
have learned that the property of the towel and the sponge 
to take up water and the lamp wick to absorb oil and the 
blotting paper to take up ink is called capillary attraction. 
Now let us see bow this thing is done. Let us take a number 
of glass tubes of different diameters, open at both ends, and 
stand them in a pan of water (Figure 4). We notice at once 
that some of the water begins to rise in the tubes above the 
level of the water in the pan. We notice further that it rises 
to different heights — the smaller the tube the higher it climbs. 
We notice also that the surface of the water in the tubes is 
concave. This is very important. 



Campbell's Soil Culture Primer 



21 



How does all this apply to the movement of soil moisture? 
Is the soil made up of tubes? No, not exactly, although there 
may be many root paths that do act as tiny capillary tubes for 
the transportation of moisture. But the soil is made up of 
minute grains with spaces between them. It is through these 
spaces that capillary action takes place. To illustrate to the 
eye the combined action of capillarity and surface tension in 
the soil, take a number of spheres (Fig. 5), dip them in oil and 
suspend them free from contact except with one another. 
The oil will not all run off. Some of it will gather at the 
bottom of the lower spheres, but a film will remain around 
each, being thicker where two spheres touch or nearly touch. 
These films are kept in place by the action of both surface 
tension and capillarity. 

How water moves in the soil, adjusting itself among the 
soil grains, is illustrated by Figure 6, which represents three 
soil grains surrounded by a film of water of unequal thickness. 
This condition could not exist for long in a state of nature, 




W/zler 



Mercury 



Fi(!. IV Fig. V 

Capillary Action in Water and Illustrates Liquid Films Around 
Mercury Soil Particles 



22 Campbell's Soil Culture Primer 




Fig. VI 

because the whole film acts as if it were enclosed by an elastic 
band. The liquid would be forced toward the grain where the 
film is thinner and toward the film of greatest curvature. 
That is how moisture moves in the soil. If the three particles 
had all the same thickness of film and some of the moisture 
were removed from one by the plant roots, withdrawing some 
of the moisture, there is a suction created — a pulling and a 
pushing — which forces the water even against gravity, toward 
the place where the moisture has been removed. A growing 
root absorbing moisture, therefore, causes the moisture content 
of the soil in its immediate neighborhood to move in its direc- 
tion. This movement of water in the soil depends largely on 
the texture of the soil itself — depends upon whether it is 
coarse or fine, the amount of moisture that it contains, and 
the grain or nap of the soil strata. 

The Run-off 

In the arid and semi-arid regions of the world (and these 
constitute one-half of the earth's surface), where the natural 
rainfall is depended on for the growth of agricultural crops, 
only about twenty-five per cent of the precipitation enters 
the ground and becomes soil water — the rest is lost in the run- 
off or is dissipated by evaporation. The dry, hard surface of 
the semi-arid plains, with their coat of buffalo grass, sheds 
water like a thatched roof. The dry soil beneath repulses 
the moisture it needs so much, and nothing but a slow, drizz- 
ling rain of several days duration will do much permanent 
good to the bare uncultivated fields. Many good, dashing 
rains that register two inches in the pluviometer fail utterly 
to penetrate the unplowed surface more than half an inch, 
affording no relief to the thirsting grass roots below. 

It is of vital importance, therefore, to prepare the surface 
of the ground to receive and absorb the moisture as it falls. 



Campbell's Soil Culture Primer 23 

As much depends upon preventing the run-off as in conserving 
the water after it has been caught in the soil. The two great 
objects are, first to get the water into the soil, and second to 
hold it there for the use of the plant. 

To prepare the soil to take in the water as it falls as rain 
or snow, is then the first object of the farmer, no matter where 
he may be located. This means loosening up the surface — 
increasing the pore space between the grains of the upper 
layer of soil. This is best done by plowing or harrowing. 
Whether a mould-board or disk plow should be used depends 
on the kind and the physical condition of the soil. The plowing 
should be deep enough to form a soil reservoir to catch and 
hold the average rainfall and not so deep as to prevent this 
same water returning by capillarity to the root-bed of the 
plants when needed. 

Loss of Soil Moisture 

Having caught the water, the next thing is to hold it — 
and hold it where you want it. But soil moisture is much 
easier to catch than it is to hold. In this respect it is like 
money — many seem able to get it, but few are able to hold 
onto it permanently. 

Soil water is lost in four ways: First, by percolation; this 
will happen in very loose soils underlaid with a subsoil of 
coarse sand, or gravel, through which the water drains; second, 
evaporation from the surface; third, by passing into and 
through a growth of weeds; and fourth, by transpiration 
through a growing crop. This last is the way we want it to 
go, and every effort should be made to compel it to take this 
route, and none other. Owing to some very recent discoveries 
the subject of transpiration has become the most important 
factor in the solution of the many difficult problems of crop 
growth and crop yields. It will be discussed later under the 
proper head. For the present we will see how water is lost 
from the soil by evaporation, and to what extent it can be 
prevented. 

By Evaporation 

While the soil is filled with air which, when the soil is 
loose in texture, or kept in good tilth, is in constant circulation, 
very little moisture is lost that way, for the reason that this 
soil atmosphere is usually near the point of saturation. But 
this is not so with the atmosphere above the surface. It is 
seldom at the point of saturation, especially in the arid and 
semi-arid regions. It is always thirsty. And when this thirst 



24 Campbell's Soil Culture Primer 

is aggravated by the heat of the summer sun, and forever 
renewed by the constant winds, every bit of moisture that 
shows its head above the surface of the ground is lapped 
up — absorbed and carried away. The great problem then is 
to keep the soil water from coming to the surface. The wind 
and the sun act on the moisture in the soil just as the flame 
acts on the oil in the wick of the lamp. As rapidly as the oil 
is consumed by the flame, or the moisture evaporated by the 
sun and wind, capillarity brings more up from below to take 
its place. When we wish to stop this evaporation of oil in 
the lamp we blow out the flame; but we can't blow out the 
sun nor stop the wind. We must resort to some other means 
to check this capillary action. We must break the connection. 
We can do it by cutting the wick in the lamp — we do it in 
the soil by forming a mulch over the surface through which 
capillarity will not act. The sun may now shine ever so warm 
and the hot winds blow — the soil moisture is securely bottled 
up and the cork that holds it in is the surface mulch. 



PERSIAN PLOW. 



Ca^npbelVs Soil Culture Primer 25 

CHAPTER 4 
THE OBJECTS OF CULTIVATION 

Knowing something of the structure and habits of plants 
and also of the movement of moisture in the soil and its rela- 
tion to the growth of the plant we are in a position to under- 
stand the objects of cultivation and to comprehend the prin- 
ciples involved in the various processes known collectively as 
soil tillage. ' 

The soil in its natural condition produces abundantly, 
especially where there is moisture, heat, and sunshine; then 
why cultivate the ground — why plow and harrow? Why not 
let nature take her course unmolested? Let us look into this. 
The objects to be secured by cultivation of the soil may be 
arranged under seven heads. 

To Destroy Plant Growth 

Paradoxical as it may seem, the first object of plowing is 
to destroy plants. If the plant growth that covers the virgin 
soil is too large for the plow, it is cut down and removed or 
burned, in order to give the plow a chance to operate. If the 
growth is short, forming a sod, it is destroyed by turning it 
under, thus exposing the roots to the action of the sun and 
weather. This is the work of the sod breaker. 

Conservation of Moisture 

The next object in order of importance is the conservation 
of moisture. This applies to all countries, no matter what the 
rainfall, but more especially to the semi-arid districts where 
the annual precipitation is supposed to be short and uncertain. 
Plowing, by rendering the surface uneven, prevents the run- 
off and forms a temporary reservoir for the storing of excessive 
rainfall until it has time to seep into the subsoil or be taken 
up by capillarity. 

To Facilitate Drainage 

In sections of the country where the rainfall is abundant 
and the soil is likely to become saturated, plowing, especially 
deep plowing, assists drainage by allowing the water to seep 
away more rapidly than it would through an unplowed surface 
and a compact subsoil. Poorly drained fields are plowed in 
"lands", the dead furrows between the lands serving as open 
ditches to carry off the surplus surface water. 



26 Campbell's Soil Culture Primer 

To Prevent Evaporation 

Turning over the furrow slice breaks the capillary connec- 
tion with the subsoil and prevents the stored water in the sub- 
soil rising beyond that point and being evaporated by the air. 
The plowed soil acts as a mulch to protect the moisture below. 
Don't get this confused with the soil mulch that is maintained 
by cultivation after plowing, for the purposes are entirely 
different. In actual practice, plowing, itself, is not relied 
upon as a mulch, to hold the moisture, but on the contrary, 
every effort is made to reestablish capillarity between the 
furrow slice and the subsoil by the use of a subsurface packer, 
relying on a surface mulch to prevent evaporation. 

To Destroy Weeds 

As the first object of the prairie breaker is to destroy 
the sod, so one object to be attained by plowing old land is to 
destroy the weeds. This is accomplished in two ways — first, 
by turning a half-grown weed under at a time that it will 
easily rot, and, second, by burying weed seeds so deep that 
they will not come up. As a general rule, weeds are surface 
growers, and when buried deeply fail to reach the surface. 

To Aerate the Soil 

One of the principle effects of plowing is soil ventilation. 
It opens the soil up so the air can better circulate through it. 
This, as we have seen, is of vital importance to the plant. 
It not only encourages nitrification, but the presence of an 
abundance of atmospheric air in conjunction with moisture 
oxidizes or rots the organic matter. By this same process 
of oxidation the soil is purified of plant excreta, and other 
toxic matter. Plowing is the first step in the process of plant 
house cleaning. 

To Liberate Plant Food 

Now we come to the last and most important object of 
plowing — the liberation of plant food. By pulverizing the 
soil, we expose its particles to the action of the elements. 
The soil moisture forms a thin film about each grain and begins 
the attack. Acids formed by decaying vegetation aid in the 
unlocking of the treasure chest, while the oxygen of the air, 
aided by the heat of the sun, completes the work. The plant 
food found in the soil is not in shape to be used by the plant — 
it must be broken up and reformed chemically to be available. 
Moisture, heat and air are the agencies that bring about this 
change, and the finer the soil is pulverized, the more readily 
can these agencies do their work. Under most conditions the 
plow that best pulverizes the soil is the best plow. 



Campbell's Soil Culture Primer 27 

When Shall We Plow? 

The question that is more frequently asked than any 
other regarding the cultivation of the soil is, "When shall we 
plow?" It is much easier to say, when we shall not plow. 
Here, again, it is very difficult to lay down a hard and fast 
rule. But this much we do know: never plow ground when 
it is dry, and never plow ground when it is wet. By observing 
these two admonitions, the farmer cannot go far wrong. 
To plow heavy soil when dry is a positive injury to the soil 
and a needless waste of power. It is always better to wait 
until the upper layer is sufficiently moist to turn over easily 
and crumble readily. This is evident to anyone who will 
think a moment — the first object of tillage is to place the 
soil in such a condition that the plant rootlets can get at the 
food that is contained in the capillary solution about the soil 
grains. If the plow throws up clods only, you have made no 
advance toward the end to be attained. These clods will 
have to be broken up or dissolved by the ordinary process 
of weathering before the plant can get a foothold. Plowing, 
therefore, should be done when the soil is in the best condition 
to respond to the pulverizing effect of the mouldboard. To 
get the soil into a proper relation with the water and air 
content it should be fined — pulverized, and this cannot be 
done by turning a hard crusted top to the bottom and then 
leaving it there with no further work until the field is all 
plowed. 

The Best Soil Condition 

Every plowman has noticed when plowing certain soils 
that are neither too wet nor too dry, just moist, how easily 
the plow is drawn and how readily the soil gi-ains separate, 
as the furrow slice breaks over and crumbles into the furrow. 
The newly turned soil seems almost alive. This is the condi- 
tion when the free water from either irrigation or from showers 
has percolated through the upper soil, leaving the capillary 
water surrounding each particle in the form of a thin film 
and the interspaces filled with air. And this condition of soil 
moisture may be maintained almost indefinitely if no weeds 
are allowed to grow and about two inches of the surface is 
kept loose and dry by cultivation. As plowing is done for 
the purpose of preparing a seed and root bed and as it is 
practically the first step in this line of preparation, it should 
be done only under the above conditions, and in the semi-arid 
sections as much in advance of the seed time as possible. 



28 Campbell's Soil Culture Primer 

providing always that the proper kind and amount of tillage 
can be given it and at the right time. 

Fall Plowing 

Is fall or spring plowing to be preferred? This is another 
question the answer to which depends almost entirely upon 
local conditions of both soil and climate. In sections where 
the rainfall is deficient, fall plowing puts the soil in condition 
to absorb and retain the winter snow and the spring rains. 
In the humid sections where the rainfall is often excessive 
in the spring, delaying the spring work, fall plowing assists 
surface drainage, thus allowing the upper soil to dry out and 
be warmed up by the sun. Under these conditions, fall plow- 
ing, if done well, often advances the planting season from ten 
to fifteen days. 

Another advantage from fall plowing is the liberation of 
plant food by weathering. The action of the atmosphere and 
the freezing and thawing process in the late fall and early 
spring have a tendency to pulverize whatever clods are left, 
giving the subsequent moisture free access to the soil grains. 
This is particularly true of clay lands, which in the sections 
of ample rainfall may be thrown up in ridges in the fall to 
facilitate, not only the process of weathering, but that of 
spring drainage. Under semi-arid conditions the problem is 
somewhat different. There, fall plowing may be practiced 
with advantage if the ground is in proper condition as to 
moisture in the fall to plow. The land, if plowed, is left in a 
better condition to absorb moisture, and, as a general rule, if 
a subsurface packer be not available at the time of the plowing, 
the root bed will have time to become firmed by the action of 
the elements. By this, we do not mean that you can afford 
to omit to pack the subsurface, for, if the fall and spring rains 
do not come to do your packing for you, you will be likely 
to fail — better not take the risk, but follow your fall plowing 
with a packer. 

Spring Plowing 

We are always in a hurry in the spring. So many things 
are to be done — things that must be done, that whatever 
work that can be done in the fall and well done, should be 
done. One great advantage from fall plowing is that so much 
of the work is done and out of the way. In the south, where 
the seasons are long, fall plowing is not an economical necessity, 
although there may be a number of advantages to be derived 
from it. Spring plowing, however, is the practice in the south 



Campbell's Soil Culture Primer 



29 



and may begin any time the soil is found to be in condition. 
In the north the case is different. Time is the main factor of 
the problem north of Mason and Dixon's line. The farmer 
must get into the field as soon as the ground will permit him 
to do so. He often has to begin before the ground is sufficiently 
dry to do the best work. In the northwest the furrow often 
exposes the frost in the ground, plowing having begun as 
soon as a three inch furrow can be cut. And this is not detri- 
mental to the soil, especially if freezing nights follow warm, 
sunny days. The plowing, with the succeeding frosts and sun- 
shine tends to di-y and warm the soil for the seed, hastening 
germination and thus lengthening the growing season. 

Subpack Spring Plowing 

Spring plowing should always be followed by the sub- 
surface packer. This should be done, no matter what you are 




Fig. VII 
Condition of the Soil as Left by the Plow 



30 



Campbell's Soil Culture Primer 



to plant. The reason is this — plowing, cutting and turning 
the furrow slice has broken capillary connection with the sub- 
soil. Under each furrow are open spaces — air spaces — often 
filled with stubble, manure or other trash that has been turned 
under by the plow. This will prevent the plowed portion of 
the soil from settling and becoming sufficiently firm to form 
a root bed. Not only that, but these spaces will prevent 
moisture from rising from the subsoil to the roots of the plant 
should the moisture in the upper or plowed portion become 
exhausted. It is clear, then, that in order to get the best 
results from your soil plowed in the spring, you must obliterate 
these air spaces and restore capillary connection, and the only 
implement that will do it is — a subsurface packer. Many 
a promising crop has been lost during a drouth when there 
was abundant moisture in the subsoil just below the furrow 
slice. 




Fig. VIII 

Condition of Soil as Left by the Subsurface Packer 



Campbell's Soil Culture Primer 31 

Preparing for the Plow 

In order to secure the best results from plowing, in many- 
cases, the land should be prepared beforehand. The stumps 
and stones not only should be removed, but corn stalks and 
other trash that litter the surface should be reduced in 
some way so that it will be readily and completely turned 
under by the mouldboard. Some farmers plan to leave stubble 
and stalks exposed so as to prevent the land from blowing, 
but there are other and better ways to accomplish this end. 
At this point it might be well to mention the practice in some 
localities of burning stubble. This should never be done, as 
the incorporation of the stubble with the soil improves the 
physical condition by lightening the soil and adding to the 
humus content. 

Disk Before Plowing 

Where small grains are grown, the disk should follow the 
harvester. Not a week after, or a day after, but immediately. 
Why should this be done? First — it crushes the stubble and 
mixes it with the soil; second — it forms a loose mulch, which 
prevents evaporation from the exposed surface; third — it 
covers whatever weed seeds that have ripened and causes 
them to germinate and grow in time to be turned under by 
the fall plowing, or killed by the autumn frosts. But an 
additional benefit, and one that must be taken into account 
when considering fall plowing, is that this disking by checking 
surface evaporation brings up the moisture from, the subsoil 
to the under side of the mulch, producing an ideal condition 
for plowing. 

This applies not only to fall but also to spring plowing. 
No matter what your crop is going to be and no matter where 
your land is, if you are going to spring plow, get into the field 
with a disk as soon as possible. If it is inclined to be a little 
wet, the disking will help to dry it out and will assist to reduce 
the stalks and stubble to a condition where they will readily 
turn under. But better still, the disking will check evapora- 
tion, and in the west, where the soil is fine, prevent to a large 
degree that curse of all fine western soils — blowing. 

When Not to Plow 

Plowing is a good thing, but we may sometimes have 
too much of a good thing. There are times when a field should 
not be plowed — better results will be obtained without it. 
The reasons for this are interesting and should be always 



32 Campbell's Soil Culture Primer 

kept in mind. Some crops are deep feeders, while others feed 
near the surface. The cereals, for instance, are shallow feeders, 
while alfalfa, potatoes, and cultivated crops generally are deep 
feeders. Now you can readily see that a crop that feeds within 
a few inches of the surface will exhaust the fertility within 
reach of its root system only, leaving the lower stratum of the soil 
still stocked with plant food. If the next crop is to be a 
shallow feeder it is the proper thing to plow this soil reasonably 
deep, turn under the exhausted surface and bring up the 
rich subsurface within reach of the roots of the plants. But 
if the next crop is to be a deep feeder, it may be well to simply 
disk the surface to get a good seed bed, providing the root bed 
appears to be in the proper physical condition. To illustrate 
this with concrete examples, we will take a potato field and 
follow with oats or wheat without plowing. The potato is 
a deep feeder and the constant cultivation given the surface 
has liberated a stock of plant food that has not been used, 
but lies waiting for a surface feeder. A corn field may be 
disked, then sown to oats or wheat and better results obtained 
than would have resulted from a thorough plowing. 

Deep Plowing 

The subject of the depth of plowing is one on which the 
"doctors" fail most woefully to agree. Certain "agricul- 
turists" advocate deep plowing — plowing from twelve to 
fourteen inches, especially in the semi-arid west. The reason 
they give for favoring this deep tillage is that it will afford 
an extensive reservoir for the storage of moisture. This, 
however, is only a half truth and like many other half truths, 
is dangerous. Stirring the soil and rendering it loose to a depth 
of from twelve to sixteen inches, will doubtless put it in con- 
dition to prevent the "run-off" in case of heavy showers; 
but, further than this, the deep tillage fad for the semi-arid 
section has no virtue. The contention that it furnishes an 
easy root bed is fallacious; so, too, is the contention that the 
soil will thus hold a greater amount of water. These deep 
plowing advocates seem to lose sight of the distinction between 
free soil water and capillary water. While the deeply plowed 
land will allow a large amount of free water to percolate 
through it, down to the subsoil, it is incapable of holding and 
delivering to the plant as much moisture as will firm a soil. 
It is capillary water and not gravitational water that the plant 
must depend upon. That is why the root bed must be firm 
and not loose. 



Camphell's Soil Culture Primer 33 

Where and When to Plow Deep 

Deep plowing has its place, but it cannot be applied 
universally. Here again it is a question of soil and climate 
conditions. If three inches is good, it does not follow that 
six inches is better. To regulate his plowing to the best ad- 
vantage, the farmer must know his soils, and must be familiar 
with the feeding habits of the crops he has been growing and 
wants to grow. He must also know the crooks and turns 
of the climate under which he proposes to operate. To advise 
one man to plow deep because another man had secured good 
results from deep plowing is like giving tooth-ache medicine 
to a man suffering from indigestion. 

Heavy soils, especially the clays that have been plowed 
from four to six inches deep for a number of years, will be 
benefited by a deep plowing — a plowing that will turn up 
the soil from a depth of eight to ten inches. This soil will be 
benefited by a loosening up and a thorough ventilation. And 
lighter soils that solidify readily will stand deep tillage, pro- 
viding a subsurface packer is used to firm the root bed if a 
crop is to be planted soon. Then again, a field that has been 
planted to a series of shallow feeding crops will bring a better 
yield if it gets a deep cultivation once in a while. 

Deep Plowing in Humid Districts 

Where the rainfall is overabundant and the soil is likely 
to become saturated, deep tillage is desirable. It is a well 
known fact that when the air is excluded by the free soil water 
the roots die of suffocation. In such cases deep tillage, by 
affording a loose and open seed bed, allows the free water to 
seep to a level below the feeding roots and the danger of 
suffocation is avoided. In many kinds of soil, deep tillage 
will take the place of underdrainage. These conditions 
prevail over large portions of the Mississippi valley and the 
southern states, where the rainfall ranges from forty to sixty 
inches. Deep tillage is also advisable where the soil is of such 
a texture that it is likely to wash and gully. Into the open 
and porous soil the rainfall finds a ready outlet and gradually 
seeps away instead of running over the surface, carrying the 
better part of the soil with it. Deep plowing, therefore, is 
largely a question of locality, climate and soil conditions. 
What would be regarded as shallow plowing in some sections 
would be regarded as deep plowing in another. 

There is no question that deep tillage is a boon to some 
soils and the salvation of a wide scope of country, especially 



34 Campbell's Soil Culture Primer 

in the south, where for a century or more the fields have been 
scratched by a one mule plow and a negro. A thorough turn- 
ing up of these soils, the upper surfaces of which have been 
packed and leached by the rains of a hundred years, would 
result in vastly increased yields through the simple fact of 
soil drainage and the liberation of plant food. 

This is not essential in the west where the soil is rich in 
inorganic matter and the subsoil is not water-logged. Let 
the farmer understand the nature of his soil, and the scientific 
principles governing capillarity and the movement of free 
soil water and he will not go far wrong on the plowing problems. 
He will be able to know when and where to plow deep and when 
and where not to plow at all. He will be able to determine 
from the physical conditions of the soil whether he best use 
a mouldboard or a disk plow, and whether his furrow should 
be five or fifteen inches deep. Simply because Mr. Brown 
plows deep or shallow and gets good results is no reason why 
yon should do the same, unless you know the physical condi- 
tions are identical. 

How deep shall I plow? No one can answer that as well 
as you can if you know your business, and if you know your 
farm. 

Subsoiling 

As a general rule, the subsoil does not contain as much 
humus and available plant food as does the upper, or surface 
soil. For this reason deep plowing that brings the subsoil 
to the surface is not the thing for the surface feeding crop. 
It often takes several years to reduce a heavy subsoil that has 
been brought to the surface by deep plowing into the proper 
physical condition to produce good crops. In such cases a 
subsoil plow that simply stirs the subsoil without bringing it 
to the surface should be used. Or for moderately deep plowing 
in such soils a disk plow is preferable to the mouldboard 
variety. The disk simply loosens the soil and shoves the 
furrow slice to one side instead of inverting it, thus bringing 
up the more or less inert subsoil. 

Breaking 

In discussing the subject of breaking we are assuming 
that the work is to be done on grass sod. Breaking among the 
stumps is a back number, for in most sections of the country 
where there are stumps, dynamite is used to remove them 
before the breaking is attempted. 



Campbell's Soil Culture Primer 35 

The first question naturally arises— how deep shall we 
plow sod land? Here again local conditions should be taken 
into consideration, but as a general rule do not cut a furrow 
more than three inches deep. Let us get at the reasons for 
this. In breaking prairie the object is to invert the sod and 
turn it over so that it will rot as quickly as possible. To this 
end the furrow slice should be turned evenly and the land 
should be immediately rolled by using a subsurface packer, 
or a surface roller heavy enough to crush the sod against the 
firm, moist soil beneath. Then a harrow should be passed 
over the field immediately to form a surface mulch and fill 
the crevices. This accomplishes two purposes — first, the air 
spaces beneath the furrow slice are obliterated and the sod is 
brought in direct contact with the moist soil beneath, not only 
establishing the broken capillary connection, but placing it 
in a position where it will rot speedily and perfectly. 

"Why not break four to six inches deep instead of three? 
Will not deep plowing afford abetter root bed for the crops?" 
you ask. Not as a general rule. If the breaking is to be 
planted or sowed to a crop immediately, the shallow furrow 
will afford a better root bed because it can be more thoroughly 
packed than the deeper plowing. It is a mistaken idea that 
the roots of the plant must have a loose and open bed in which 
to grow. What they do want is firm and well hydrated soil. 
And anyone who is observing will note that the roots of the 
average plant encounter little or no difficulty in penetrating 
the soil beneath the furrow slice, providing that portion of 
the soil contains the proper amount of moisture. 




36 Campbell's Soil Culture Primer 

CHAPTER 5 

PURPOSES OF SCIENTIFIC TILLAGE 

The purposes of scientific tillage of the soil as expressed 
by King are as follows: 

(1) To secure a thorough surface uniformity of the field 
so that an equally vigorous growth may take place over the 
entire area. 

(2) To develop and maintain a large effective depth of 
soil, so that there shall be ample living room, an extensive 
feeding surface and large storage capacity for moisture and 
available plant food material. 

(3) To increase the humus of the soil through a deep 
and extensive incorporation of organic matter, so that there 
may be a strong growth of soil micro-organisms and the 
maintenance of a high content of water-soluble plant food 
material. 

(4) To improve the tilth and maintain the best structural 
condition of the soil, so that the roots of the crop and the soil 
organisms may spread readily and widely to place themselves 
in the closest contact with the largest amount of food material. 

(5) To control the amount, to regulate the movement, 
and to determine the availability of soil moisture, so that 
there shall never be an excess or a deficiency of this indispens- 
able carrier of food material to and through the plant. 

(6) To determine the amount, movement and availability 
of the water-soluble plant food material present in the soil 
so that growth may be both rapid, normal and continuous 
to the end of the season. 

(7) To convert the entire root zone of the soil into a 
commodious, sanitary living and feeding place, perfectly 
adapted to the needs of the roots of the crop and to the soil 
organisms — adequately drained, perfectly ventilated and suf- 
ficiently warm. 

(8) To reduce the waste of plant food materials through 
the destruction of weeds and the prevention of their growth. 

(9) To preserve the soil and prevent waste through 
surface washing and drifting by winds. 

Must Know Soils and Plants 

The farmer to till the ground intelligently and effectively 
must have an intimate knowledge of the structure and physical 
characteristics of the soil. He must know what the results of 
certain definite treatments will be. Not only this, but he 
must be thoroughly acquainted with the habits and demands 



Campbell's Soil Culture Primer 37 

of growing crops. He must know how to plan his campaign 
against the enemy — the army of noxious weeds that is forever 
invading his territory. He must know, to some extent at 
least, the relation of plant growth to moisture, temperature 
and light. So complex are the elements that enter into the 
problems of plant life and so many are beyond the control 
of man that it takes, not only a thorough knowledge of the 
physical laws that govern the relation of the plant to the soil, 
but it requires a sound judgment, coupled with experience to 
do the proper thing at the right time. The necessity for 
knowing things and observing the minutest details cannot 
be too strongly impressed upon the mind of the reader. Ob- 
serve all things and hold fast to what is good, 

A Confusion of Terms 

The terms seed bed and root bed are used interchangeably 
by most writers and speakers on agricultural subjects. This 
is somewhat confusing as the seed and root beds of most 
plants are entirely distinct propositions, with functions as 
different as the methods of their preparation. In the prepara- 
tion of the seed bed, the farmer should keep in mind the 
germination of the seed and the development of the plantlet. 
In the preparation of the root bed he should have in view only 
the growth and maturity of the crop. This mixing of terms 
that mean entirely different things, like the indiscriminate use 
of "summer fallow" has been the cause of countless errors 
with great material loss. In agricultural parlance, "a rose 
by any other name" does not always smell as sweet. Let us, 
therefore, fix clearly in our minds the distinction between 
seed bed and root bed. 

The Seed Bed 

In the growth of a plant, whether it be a bean stalk or 
an oak, the first step after the seed is planted is germination — 
the bursting of the seed cover and the development of the 
embryonic plant within. And, for the purpose of clearness, 
we will include in the term germination the putting forth of 
the plumule and its upward reach to the light as well as the 
development of the tiny rootlets that establish the plantlet 
in its relation to the soil. These processes take place in the 
seed bed — in the first inch or two of surface soil. It will be 
clear to everyone, that owing to the delicate nature of all new- 
born plants, this seed bed should be prepared with especial 
care as to physical texture. Not only that, but care should 
be taken to see that both the temperature and the moisture 
content of the seed bed are such that germination will be 



38 



Camphell's Soil Culture Primer 



quick and the early growth rapid, for upon these first few 
days of the hfe of the plant the harvest often depends. 
The Root Bed 

Below the seed bed lies the realm of the roots — the feeding 
field of the growing crops. This root bed — this feeding field — 
is an indefinite and unsurveyed area; it may be confined to 
the first six inches of soil beneath the seed bed or it may 
extend to a depth of twenty feet. The extent depends entirely 
on the "root habit" of the particular plant. As a general 
statement, however, we would say that the root bed of. the 
average cultivated field crop is found within the first twelve 
inches of the surface. While the seed bed and the root bed 
are in a sense distinct, they merge into each other. The 
lower part of one and the upper part of the other constitute 
a kind of neutral territory over which the laws governing both 
extend. It will be seen, therefore, that while the seed bed is 
under the control of the farmer and gardener and can be 
prepared by the ordinary tillage implements, it is different with 
the root bed — only the upper stratum of the root bed can be 
reached directly by any implement so far invented, although 
the necessity for thorough preparation is becoming more and 
more apparent as the laws governing plant growth are better 
understood. 




Fig. IX 

Showing an Ideal Seed and Root Bed 



Campbell's Soil Culture Primer 39 

CHAPTER 6 
PACKING AND PACKERS 

Surface and Subsurface 

The lack of a clear conception of the difference between 
the seed and root bed is, without doubt, responsible for the 
confusion that exists in the popular mind in regard to packing 
the soil. No distinction seems to be made between surface 
and subsurface packing. The terms clod crusher, surface 
packer, roller, and subsurface packer are all applied indis- 
criminately to the same implement. Even manufacturers of 
a corrugate roller advertise it as a "subsurface" packer. Nor 
does the babble of verbal confusion stop here. Some speak 
of "subsoil" packers. And a noted authority in a noted 
book speaks of a subsurface packer designed to pack the 
"subsoil to a depth of from eighteen to twenty-four inches below 
the surface." This looseness of expression is owing to a lack 
of definite knowledge regarding the principles involved in 
soil packing. When these principles are once understood, 
confusion of terms is impossible. 

The Distinction 

Before going further let us get the distinction between 
surface and subsurface packing clearly in our minds. Surface 
packing is a comparatively old practice and applies exclusively 
to the seed bed. It is accomplished by the roller, the clod 
crusher, or in some instances, by a "float." The process 
usually applied after seeding firms and smooths the surface 
of the ground. Subsurface packing affects the root bed. It 
is intended to obliterate air spaces left under the turned 
furrow slice and firm the lower portion of the plowed ground — 
the object being to pulverize and compact the under surface 
and reestablish capillary connection with the unplowed portion 
of the soil. Subsurface packing is one of the new things of the 
new agriculture and had its origin in the semi-arid west. 
While there are numerous devices for packing the surface, 
there is so far but one subsurface packer, composed of a series 
of skeleton wheels with a wedge-shaped rim that cuts down 
into the furrow slice with a downward and lateral pressure. 
The subsurface packer not only pulverizes clods, obliterates 
air spaces left by the turned furrow, and reestablishes capillary 
connection with the subsoil, but it also leaves the surface 
loose and unpacked, thus forming a mulch to protect the 
packed portion beneath. 



40 



CampheU's Soil Culture Prhner 



Preparation of the Seed Bed 

With the distinction between the seed bed and the root 
bed, and also that between surface and subsurface packing, 
clearly in our minds, we can proceed with the preparation of 
the soil for the reception of the seed. A crop that is well 
started is half grown; and in starting a crop the next thing 
in importance to pure and virile seed is a clean and well con- 
ditioned seed bed. Plowing, the first act of tillage, is supposed 
to prepare the foundation for both the seed bed and the root 
bed. If it fails to do this, it has not accomplished its purpose. 
We will assume that the plowing has been properly done and 
the under surface firmed by the use of a subsurface packer. 
The next step in the preparation of the seed bed is to harrow 
the plowed surface, using either a disk or a spike-tooth harrow, 
according to the physical condition of the soil, the object being 
to pulverize all clods, level the surface and establish a soil 
mulch on the surface to prevent evaporation. This mulch 
should be from two to two and one-half inches in depth. 
Bear in mind that we are talking now about the seed bed only. 




_t> \ 



S:l ""X -J^ "^.':.*^^ 



'i \i^ ■;■ ■ ^'"t^:, -fis^i^^ 



Fig. X 
A Subsurface Packer in Action 



Campbell's Soil Culture Primer 41 

Use of Rollers 

Seed to germinate quickly must be planted sufficiently 
deep to come into direct contact with moist soil and the moist 
soil must be fine and firm, so that the soil particles, surrounded 
as they are with a film of water, will be closely crowded against 
each individual grain of seed. This is necessary, not because 
the seed requires the plant food locked up in the soil grains, 
but because it needs the moisture. To render this seed bed 
firm after the fining effect of the harrow, the surface roller 
or clod crusher is often used with beneficial results. Where 
there is abundant moisture, or the soil is light in texture, or 
inclined to be cloddy, the use of the surface roller will, no 
doubt, hasten germination. This firming of the upper layer 
of the soil in which the seed is imbedded brings about the 
conditions necessary to render active the dormant protoplasmic 
cells of the seed. This is why the gardener, when planting 
radishes, onions, and other small garden seeds in well prepared 
beds uses a board to stand on and to firm the loose surface 
over the rows of seed. And this is also the reason why in the 
old days of planting corn by hand, the "man with the hoe" 
was careful to step on each hill as he covered the seed. But 
in giving the finishing touches to the seed bed the roller, or 
as it is more often called, the surface packer, should be used 
with great discretion. A surface packer is a good thing to 
have on the farm and it is often a good thing to use, but the 
farmer must know when to use it and when to let it alone. 

In the semi-arid west where the soil is likely to "blow" 
the roller, or the float, should seldom be used, for the reason 
that both have a tendency to pulverize the surface and leave 
it at the mercy of the wind. For all purposes of clod crushing 
and packing, the subsurface packer of the Campbell type 
that firms the under portion while leaving the surface loose 
and rough is better. The coarse mulch left by the subsurface 
packer meets the requirements of the western plains much 
better than the fine or "dust mulch" left by the roller or the 
float. The use of soil packers is largely a question of geography 
and soil physics. The roller and the float may work all right 
where there is abundant moisture and no high winds, but in 
the semi-arid west — look out. 

Any one can understand that when we attempt to firm 
the seed bed with a roller the direct effect is to firm the surface 
only, leaving it smooth and compact. The effect, depending 
on the weight of the roller, seldom extends more than an inch 
or two below the surface. This will help germination, but by 



42 Campbell's Soil Culture Primer 

firming the surface, it has placed within the upper soil a million 
little pumps, that in a few days, if nothing be done to prevent, 
will exhaust the seed bed of its store of moisture. Therefore, 
when you use the surface packer, follow it immediately with 
some kind of an implement to loosen the surface again, forming 
a light mulch to check evaporation. There are individual 
exceptions to this rule, but it applies generally to all soils and 
all climates. 

The Float 

In place of a roller many good farmers use a float made of 
planks joined together and overlapping like the clapboards 
of a house for crushing clods and smoothing the surface. This 
kind of a drag when weighted has much the same effect as 
the roller, so far as packing the seed bed is concerned. As a 
clod crusher its action is superior to that of the roller as it 
grinds the clods instead of pressing them down into the seed 
bed. The float, too, is a better leveler than the roller, and 
a level surface for most crops is greatly to be desired, as we 
shall see later on. A drag m.ade like the celebrated King road 
drag is used for leveling and packing the seed bed before 
planting. The King drag may be made of two 2x8 planks 
ten feet long, placed on edge three feet apart — the ends over- 
lapping about a foot. Cross pieces of 2x6 are mortised in to 
hold the planks in place; across these, boards are nailed to 
form a floor on which the driver stands. It is operated at a 
slight angle. The amount of angle can be governed by the 
driver shifting his weight. 

Preparing the Seed Bed 

It is hardly possible to put too much stress on the necessity 
of thoroughly pulverizing and packing the seed bed. One of the 
most complete practical illustrations of this was brought out 
on the demonstration farm at Hill City, Kansas, in the germina- 
tion and growth of the wheat sown in the fall of 1901. The 
ground had been prepared with the greatest possible care, 
having been plowed seven inches deep when the soil was in 
a moist condition, kept so by disking and harrowing the 
surface. The plow was followed closely by a subsurface 
packer and that by an Acme harrow. By doing all the work 
at the proper time we had secured a very favorable physical 
condition of the upper soil. At the time of seeding, October 8, 
9 and 10, there was a fine, loose mulch on the surface, two and 
a half inches deep. The soil immediately beneath the mulch 
was firm and moist. The wheat was put in with a shoe drill, 



Campbell's Soil Culture Primer 



43 



about one-half inch into the firm moist soil under the mulch. 
Less than one-half bushel of seed was used to the acre. As a 
result germination and growth were both rapid. The fourth 
day, as regularly as the days came, after seeding, the little green 
spears could be seen the entire length of the rows. On the 
seventh day these leaves measured from three to four inches. 
This is not all. On the sixteenth day of November this wheat 
was taller and thicker than an adjacent field sown the sixteenth 
day of September with one and one-quarter bushel of seed. 




Fig. XI 

Showing Proper and Improper Preparation of Seed and Root Beds 



Figure 11 represents two conditions of soil. On the right 
we have the more common condition, prepared without care, 
the grain of wheat deposited in a coarse, loose soil. In such 
a seed bed wheat will remain the entire fall without germinat- 
ing, or it may germinate after a light shower only to wither 
and die later for lack of a permanent water supply. On the 
left we have an ideal condition — a condition that can be 
easily secured with care and without much additional expense. 



44 Campbell's Soil Culture Priyner 

By the use of the subsurface packer when the soil is in the 
proper shape, we get the fine, even, firm soil as shown to a 
depth of seven inches. Then with the harrow, the Acme, 
or the mulcher we get a soil mulch (not a dust mulch) about 
two inches deep. With a shoe or double disk drill a V-shaped 
opening is obtained and the grain dropped about one inch into 
the firm soil. As it reaches the bottom it is surrounded on 
all sides but the top with a fine, firm, moist soil. It is all 
ready to germinate, take root, and come up. 

Preparation of the Root Bed 

The seed bed should be fine, firm and warm, that the 
seed may be able to secure moisture. It must also be brought 
to a temperature that will unlock the prepared food stored in 
the seed for the use of the plantlet. The root bed should 
be fine and firm and moist, and warm, that a soil solution 
may be prepared and impregnated with inorganic plant food, 
and that the roots may reach out and gather it in without 
difficulty. The root bed should be put in such a condition 
that will not only release the greatest amount of inorganic 
plant food, but which will enable the roots to gather in the 
necessary food for the plants with the least effort. But while 
it is a comparatively easy matter to get at the seed bed and 
put it in condition, it is not so easy to reach the entire root 
bed with ordinary cultural implements. By what means can 
the farmer reach and control the conditions of the root bed 
or the ordinary field crops? This brings us to the subject of 
subsurface packing. 

Subsurface Packing 

The best plowing leaves the underside of the furrow slice 
resting lightly on the compact under soil beneath. When the 
dry surface, containing always a certain amount of trash, is 
turned under there will always remain air cavities, the size 
depending on the physical condition of the soil and the kind 
of plow used. The connection between the plowed and the 
unplowed portions of the soil has been broken. It does not 
matter how deep you plow, the result is the same. The soil 
of a newly plowed field, if in the proper condition when plowed, 
is always too loose for either an ideal seed or root bed. Capil- 
lary connection with the under soil has been broken, and no 
matter how compact you get the upper stratum — the seed 
bed — if a drouth should occur the plant will soon exhaust 
the moisture in this upper layer, and not being able to get 
any up from below, it will die of thirst with an abundance of 



Campbell's Soil Culture Primer 



45 



capillary water just beyond its reach. What is to be done? 
There is but one thing to do, and that is to pack the sub- 
surface — pack the entire furrow slice so that the air cavities 
will be filled and connection with the subsoil reestablished. 
But a surface roller, heavy enough to do that, will pack the 
top soil to such a degree that it will lose its water content very 
rapidly through surface evaporation. This result, as we have 
seen, may be prevented by the immediate use of the harrow. 
These surface rollers and clod crushers are of no value what- 
ever when it comes to packing the subsurface. 





mimmK& 



Fig. Xir 

The Subsurface of a Plowed Field as it Appeared After a Thorough 

Surface HarrowinsT 



The Subsurface Packer 

The Campbell subsurface packer, and those built after 
the Campbell model, pack the under surface of the furrow 
slice by means of wheels with a wedge-shaped rim that cuts 
into the soil from three to four inches, depending on the amount 
of weight carried by the packer and the condition of the soil. 
The construction of the packer wheels allows the dirt to fall 
in above the rims, thus leaving a coarse mulch on the surface. 
The principles on which the Campbell packer acts are simple 
and the action effective. It reverses the action of the surface 
packers by packing the subsurface (not the subsoil), leaving 



46 



Campbell's Soil Culture Primer 



the surface loose and unpacked. Various implements have 
been tried to bring about these results, but none so far have 
turned the trick. A disk harrow, with the disks set straight, 
is used by some in the place of a subsurface packer; but the 
very principles on which the disk is constructed make it a 
loosener of the soil rather than a soil packer. The use of the 
disk in putting the plowed field in good tilth, without doubt, 
will help nature do her own packing, but it will never do the 
work of a subsurface packer any more than a spike-tooth 
harrow will do the work of a disk. 




Fig. XIII 

The Subsurface of a Plowed Field After Subpacking and a Thorough 

Harrowing 

When to Use the Subsurface Packer 

The use of the subsurface packer depends on the soil 
itself and also on the condition in which it happens to be. 
Don't use a subsurface packer on every field, nor on all soils 
at all times. Great discretion should be used. Some heavy 
soils that pack readily under the action of the weather might 
be injured by the use of a subsurface packer. Don't pack the 
soil unless it needs it. If planting is to follow plowing, a sub- 
surface packer should be used. It should follow the plow im- 
mediately and in its turn should be followed by a harrow to 
put on the proper surface mulch. 



Campbell's Soil Culture Primer 47 

Advantages of Subsurface Packer 

The use of the subsurface packer not only reestabhshes 
capillary connection with the under soil, but by firming the 
plowed portion it increases the water-holding capacity of the 
soil near the surface and thus affords the roots a firm and 
rich feeding ground. The time of plowing has something to 
do with the problem of subpacking. Fall plowing should be 
subpacked, but the necessity is not so great as it is in the case 
of spring plowing, for the reason that nature, through the 
agency of the frosts of winter and the rains of late fall and 
early spring, if there are any, will do to some extent the 
work of the subsurface packer. But if there should be no 
fall nor spring rains, as is often the case in the semi-arid west, 
there will be little packing done by nature. It is better, there- 
fore, to use the subsurface packer on fall plowing than to take 
any chances on nature doing the work. On spring plowing, 
however, when a crop is to be planted immediately, the sub- 
surface packer should never be omitted. It should follow the 
plow, and the deeper the plowing the greater the necessity for 
packing. 

Prevents Soil Drifting 

The fact that subsurface packing will prevent to a large 
extent soil drifting is pretty well established. The scientific 
principles involved are not clearly understood, but it is believed 
that a well packed soil, possessing as it does a high degree of 
capillarity up to within a few inches of the surface, retains 
its vitality longer and imparts that virile condition even to 
the surface mulch. Whatever be the reason, the universal 
experience from North Dakota to Texas has been that, while 
fields handled by the ordinary methods and unpacked were 
blown out of their fences, the subpacked field remained unin- 
jured. 




48 Campbell's Soil Culture Primer 

CHAPTER 7 

CULTIVATION 

Surface Cultivation 

With the root bed made fine and firm and the seed bed 
properly prepared, the seed germinated and the plants above 
ground, the next act on the program is cultivation. The sur- 
face of the ground must be so handled that the moisture will 
not escape by evaporation nor the weeds pump it out. 

How deep shall we cultivate? This question is the twin 
of how deep shall we plow. Neither can be answered unless 
the soil and climatic conditions, the kind of crop or crops 
that have previously occupied the soil, as well as the kind of 
crops to be grown are all known. A deep-feeding crop will 
be benefited while a shallow-feeding crop will be ruined by 
deep cultivation. Leaving out of consideration the root habits 
of the crop to be grown, level surface cultivation has certain 
advantages that ought to be understood by every farmer. 
It was once thought necessary to hill potatoes, and in many 
localities, especially in the south and east, deep cultivation 
is recommended for both corn and cotton. This advice may 
be good if the land is not well drained. As a surface drainage 
scheme this may have some virtue, but from any other point 
of view it is a bad practice. Let us get at the facts. 

The potato is a deep feeder. If the seed and root bed be 
properly prepared the roots will spread out in every direction 
where there is moisture. If the surface of the field be kept 
level with a proper mulch on top, the soil moisture will be 
brought up and held near the surface within easy reach of 
the roots. Now, if the interspaces be cultivated deeply, so 
as to ridge or hill the potato plants, not only will many lateral 
roots be cut or exposed, but a larger surface will be exposed 
to the drying action of the sun and wind, while the actual 
feeding ground of the roots — the root bed — will be narrowed 
and limited to the few square feet about the hill. The same 
principles apply to the cultivation of corn and cotton. Shallow 
culture not only conserves the greatest amount of moisture, 
but it widens the root bed, increases the available feeding 
ground and leaves the field in better shape for the next year's 
tillage. And this brings us to another question — shall we 
employ ridge or level culture? 



CamphelVs Soil Culture Primer 49 

Level Culture 

A certain degree of heat is absolutely necessary to the 
germination of seed and the growth of plants. It is necessary 
because the chemical action that takes place in the awakening 
of the germ of the seed and the assimilation by che plantlet 
of the stored food demands a certain degree of heat. In addi- 
tion to this, the physical process known as osmosis, by which 
the roots of the plants gather in the solution is hastened by 
a high soil temperature. We know, also, in a vague way, 
that the microscopic organisms that inhabit the soil — the soil 
bacteria, that contribute so much to the health and growth 
of plants, thrive best in optimum soil temperatures. We 
know positively that the higher the temperature of the soil 
moisture, the greater will be the liberation of inorganic plant 
food and consequently the richer will be the soil solution. 
With these facts in mind it is easy to see the advantage of any 
system of cultivation that tends to quickly and permanently 
warm the soil, and this where the soil is well drained is accom- 
plished best by level cultivation. As a general rule, and for 
a large majority of crops raised by inter-tillage, level culture 
is advisable. It hastens germination of the seed by increasing 
the soil temperature; it produces an even distribution of soil 
moisture and plant food. As a result the stand is regular and 
even and the grade of the ripened grain uniform. 

Ridging and Listing 

In some localities, especially in the south, where spring 
rains are likely to be excessive, the natives practice ridging 
for corn and cotton. Two furrows are backset and the seed 
planted on the ridge, or four furrows are backset and the seed 
planted along the edges of the dead furrow. The object of 
this method is to save the young plants from drowning by 
supplying a means of surface drainage to carry off the surplus 
water. This is but a make-shift and should have no place 
in the permanent agricultural practice of a community. Deep 
plowing and underdrainage will accomplish the same results, 
leaving the surface level and the available inorganic plant 
food evenly distributed throughout the seed and root beds. 

Where the rainfall is supposed to be insufficient, or 
unreliable, the practice of listing is extensively employed, 
especially for corn. Listing is just the reverse of ridging. A 
double furrow is thrown up and the seed deposited in the 
ditch thus formed, the idea being that the deeper the plant 
is rooted, the better it will be able to stand a drouth — or, in 



50 Campbell's Soil Culture Primer 

other words, the deeper it is planted the better able it will be 
to secure moisture from the soil. This, as we have seen, is not 
necessarily true. If the firm soil of the root bed is deep, the 
seed should be planted within easy reach of it. The practice 
of listing corn presents the advantage of a rough surface 
which is to a certain extent a protection against soil drifting 
in sections where high winds prevail. It has an advantage 
also in the fact that the inter-culture that follows never inter- 
feres with the main roots of the plants. These observations 
are sufficient for our present purpose. 

As to Time of Cultivation 

The proper time for cultivating a field is one that cannot 
be fixed without much thought, observation, and judgment 
by the farmer, especially if he would get the best results. 
Always cultivate immediately, or as soon after a rain as con- 
ditions will permit you on the field, and the soil is sufficiently 
dried so that it will not adhere to the cultivator teeth, or tools 
used. We do not mean by this that the soil should be ab- 
solutely dry on the surface. It is an error to wait for that time, 
for the moment the surface is apparently dry the crust begins 
to form. It is desirable to catch the ground just before this 
time when all the soil is simply moist and then there is a free 
and ready separation of all particles. In this condition the 
cultivator runs the easiest, the mulch made the finest and 
lies up light and loose. If the soil is a little too wet it settles, 
and not infrequently forms absolute and perfect connection 
with the firm soil below, steadily carrying moisture to the 
surface. If too dry the cultivator produces an imperfect 
mulch that gives us but little protection. 

Another very important fact is that every moment's 
delay after the soil reaches the proper condition causes you 
to lose water very fast. It is at the rate of a quart or over 
per square foot per day, providing it is clear sunny weather, 
and even more in case of hot winds. The more intense the 
heat the more frequently it is necessary to cultivate. A very 
good rule is to watch the condition of the firm soil just beneath 
the loose mulch or cultivated portion, and whenever the 
surface of this firm soil begins to show dryness it is high time 
to commence cultivating again. 



Campbell's Soil Culture Primer 51 

CHAPTER 8 
THE SOIL MULCH 

Evaporation 

Evaporation of moisture takes place from the surface of 
a body of water, or from the exposed surface of most materials. 
It is increased by a continuous change of air and a high tem- 
perature. Constant winds, and a hot, dry atmosphere are 
favorable to rapid evaporation from damp surfaces exposed 
to the air and sun. If you want to prevent evaporation from 
a tub of water you would cover it up. If you want to prevent 
evaporation from the surface of a field, cover it up. To protect 
the roots of the orchard trees and the small fruits in the garden 
from the frosts in the winter, and to keep the ground about 
them cool in the spring and moist in the summer our grand- 
fathers covered the ground with a layer of straw, forming a 
straw mulch. Nature does the same thing annually when 
left to herself — she covers the surface of the ground with a 
mulch of grass or leaves. This not only arrests the rainfall, 
but prevents evaporation to a degree depending on the thick- 
ness of the mulch. Throw a blanket on a lawn and, although 
no rain falls and the blanket appears perfectly dry, in a few 
days the soil under the blanket will be damp clear to the 
surface. Now, to prevent evaporation from a cultivated field, 
cover it up with a mulch, not of leaves, or grass, or straw, 
but of particles of earth that will act as the lid on the tub of 
water, or as the blanket on the lawn. This mulch can be formed 
with the harrow, either the disk or the spike-tooth, and can 
be maintained by the ordinary cultural implements adapted 
to the crop being grown. 

Avoid a Dust Mulch 

Loose talkers and equally loose writers on agricultural 
subjects have advocated the maintenance of a "dust mulch," 
and apply that name to all soil mulches. This is much to be 
regretted for it leads to all kinds of confusion. The farmer 
is advised to maintain a "dust mulch" when a soil mulch 
made up of small dirt clods from the size of a pea to that of a 
large marble is desired. A dust mulch renders the surface soil 
lifeless and easily crusted and even puddled by a dashing rain. 
It also forms an almost impervious barrier to percolation — it 
repulses the moistui'e from both below and above. When the 
harrow is used immediately after the plow, or following a 
rain, the surface will be left in an ideal condition to prevent 



52 Campbell's Soil Cidture Primer 

the loss of the moisture already in the ground and to receive 
future rainfalls. It is often necessary to work ground until 
the surface is reduced to something like a dust, but this con- 
dition should be avoided as far as possible. 

When to Establish a Mulch 

The most important factor in the problem of crop pro- 
duction is the conservation of soil moisture, and we use this 
word conservation in its fullest sense, meaning not only gather- 
ing and holding it, but so holding it as to render available to 
the plant, food within the soil solution. The mulch being the 
lid to prevent the escape of this moisture, the when and the 
how of its placing on are of vital importance. While a crop 
is growing, and while it is standing on the field it prevents, 
to a large extent, evaporation from the surface of the soil. 
But when it is removed, the wind and the sun begin to pump 
out the moisture and carry it away. This is especially true 
of small grains and grasses that have covered the land like a 
blanket, shielding the surface from the direct rays of the sun 
and the sweep of the wind. The mulch, therefore, should be 
placed upon the field as soon as the grain is removed. 

Disk Should Follow Harvester 

No time should be lost in putting on the lid — not even a 
day. The disk harrow which is the best possible implement 
for this purpose should follow the harvester, cutting the 
stubble and slicing the surface crust, thus forming a mulch 
that will not only prevent the evaporation of the subsoil 
moisture, but facilitate the absorption of any subsequent fall 
rains. The benefit of disking the stubble, however, does not 
stop here; it brings the soil moisture from below up to the 
under surface of the mulch and holds it there. No matter how 
dry the surface crust may be at harvest time, if there is any 
moisture in the soil, and there usually is, if the field be thor- 
oughly disked at once, you will note that in a week or ten 
days the soil immediately under the mulch is moist and in 
prime condition to plow. 

Disk Before Plowing 

The above is one reason why all fields, especially in the 
fall, should be disked before plowing. There are other reasons 
which are equally as cogent. For instance, the seed and root 
beds are left in much better shape by the plow if the surface 
has been thoroughly fined by the action of the disk. This will 
become evident if you give it a moment's thought. When- 
ever a field with a rough or uneven surface is plowed — a field 



CampbeU's Soil Culture Primer 53 

that has been in corn or potatoes and which did not receive 
level culture the previous year, and which also is covered 
with corn stalks or other rubbish — the furrow slice never 
completely fills the vacant furrow with a compact, well pulver- 
ized soil, but leaves the surface uneven and cloddy. But this 
is not the worst of it — the surface can be easily taken care of — 
the trouble is with the subsurface. This is left full of air 
spaces caused by the rubbish and clods from the uneven 
surface holding up the furrow slice. This condition can be 
largely remedied and a much more compact seed and root 
bed left by the plow if the surface crust, the clods and the 
rubbish, has been subject to the action of the disk. These 
results of plowing disked and undisked ground are shown in 
figure 20 page 89. 

Harrowing Small Grain 

Small grain should be harrowed to destroy weeds and 
maintain a surface mulch. When a heavy rain forms a crust 
on the surface of a wheat field when the wheat is not sufficiently 
high to shade the ground, more moisture will be lost by evapora- 
tion than fell as rain unless the crust be destroyed by some 
light cultural implement. To kill weeds in a young wheat 
field, or break up any crust that may form, the spike-tooth 
harrow is usually used. The harrow should be used with the 
teeth set back. If the stand is too thick, the harrow should 
be drawn at right angles to the drill rows, otherwise in the 
same direction. The objects of harrowing small grains are 
to conserve the moisture, kill the weeds that may be starting, 
and to thin the stand when too thick; but the principle object 
is to bottle up the moisture and hold it for the plant. In 
the spring, when the winds are high and the stand of grain is 
small, evaporation from an unmulched surface is very gi'eat. 
It is then that the plant needs the moisture near the surface 
in the region of its roots. If a light mulch can be maintained 
until the plant gets larger so that it will shade the ground, 
the danger from excessive evaporation is much less. 

When to Harrow 

Do not harrow grain simply to be harrowing. If there is 
no moisture to conserve, no crust to break, nor weeds to 
destroy, there is no need to harrow. There is no virtue in 
simply doing the work if there is no demand for it. The man 
who resolved to harrow his wheat every week knew neither 
the why nor the when of his work and would be likely to do 
his field more harm than good. Care must be taken to catch 



54 Campbell's Soil Culture Primer 

the soil when it is moist, if possible. The best time is when 
the grain is beginning to stool, or when it is about four inches 
high. If, however, the field should pass through the spring 
without rain enough to settle the mulch, it is not necessary 
to harrow — nothing is to be gained; but if a heavy rain comes 
and settles the mulch, you must harrow again. The mulch 
should be kept in good shape until the foliage covers the 
ground. The loose surface will facilitate the free circulation 
of the air, so much to be desired. 

Harrowing Corn 

The harrow can be used with beneficial effect on the corn 
field after the plants are well up, especially where level culture 
has been employed. The principles involved and the objects 
to be obtained are the same as in harrowing smaller grain — 
the formation of a mulch to prevent evaporation and the 
destruction of young weeds. Harrowing a field of corn or any 
other inter-culture crop after a rain is the most effectual and 
economical method of saving the m^oisture and at the same 
time preventing weed growth. For this use a weeder is pref- 
erable. The spike-tooth harrow can be used, but the teeth 
must not be set too slanting or they will tear out the corn. 
This method of culture can be employed until the corn is a 
foot high, providing the work is done only in the afternoon, 
when the corn plant will receive a great deal of punishment 
without injury. 

The Subsurface Crust 

When the hot sun of June and July beats down on the 
cultivated fields, the temperature of the soil mulch will often 
rise above the 100 limit. This is good for the crops if they 
have a plentiful supply of soil moisture within reach of their 
roots and the soil circulation is all right. But this excessive 
heat brings up the soil moisture through the capillary tubes 
with the energy of a force pump. And coming from below, this 
moisture contains various salts in solution. As it rises a great 
part of it is absorbed by the roots which select the mineral 
ingredients needed; the remaining solution heavily charged 
with inorganic matter rises until it reaches the under side of 
the mulch where the excessive heat turns it into vapor which 
escapes through the mulch into the outer air, leaving the salts 
behind. This, if allowed to continue, will soon form a crust 
between the mulch and the moist soil beneath. When once 
formed, this crust shuts out the air — actually seals up the soil, 
and although there is plenty of moisture beneath the crust 



CampbelVs Soil Culture Primer 



55 



the crop will wilt and die, not because of a lack of moisture, 
but because the respiration is shut off. The plants will 
suffocate. 

The Remedy 

The remedy for this condition is not deeper cultivation, 
for that in most cases means the cutting off of the main feeding 
roots of the plants. The remedy might be worse than the 
disease. The thing to do is to prevent the crust from forming 
by timely cultivation. This crust is likely to form under the 
mulch in the corn fields during excessively hot seasons. A 
careful watch should be kept on the condition of the soil just 
beneath the mulch. When this begins to show signs of hard- 





FiG. XIV 

Showing the Effect of a Rain in Settling a Soil Mulch 



ness, get into the field at once and stir your mulch, break up 
the capillary channels that are letting the steam out and 
evaporation will cease and the crust will not form. Caring 
for a field of corn so that a subsurface crust will not form 
during, long, hot, dry spells is a sure test of the knowledge 
and ability of the farmers of the middle west. A word of 
caution and another of advice might not be out of place here. 
If the weather is hot and dry, and so continues for a number 
of days, no matter how complete your mulch appears, nor 
how thrifty your corn looks, go over your field and here and 
there scrape away the mulch and feel of the soil beneath. 
If you find signs of a forming crust, get busy. Don't go any 



56 CampheU's Soil Culture Primer 

deeper with your implement, but stir the mulch and keep it 
stirred until the danger is over. You may thus be able to 
save a crop. 

Keeping the Mulch in Condition 

There are many important reasons why great care should 
be taken to keep the mulch in perfect condition and prevent 
the loss as far as possible of any moisture by evaporation 
from the surface of the soil. The following paragraph taken 
from King's book on The Soil conveys some important in- 
formation along this line. We quote this because it bears the 
figures of his own practical observation at various depths 
in the soil, showing the effect not only of the surface soil 
getting too dry but of light showers. He says: 

"When the surface soil has its water content reduced so 
the upper six to twelve inches are beginning to get dry the 
rate of capillary rise of water through it is decreased and it 
begins to assume the properties of a mulch. But when this 
condition has been reached, if a rain increases the thickness 
of the water film on the soil grains without causing percolation, 
the capillary flow may be so certain that the surface foot draws 
upon the deeper soil moisture at a more rapid rate than before, 
causing a trans-location of the lower soil moisture, the deeper 
soil becoming measurably drier soon after such a rain than 
it was before, while the surface foot is found to contain more 
water than has fallen upon it." 




The Primitive Hand Harrow 



CampheU's Soil Culture Primer 57 



CHAPTER 9 

SUMMER TILLAGE 

The Agricultural Trinity 

To plow, to sow, and to reap, are the three acts of the 
great agricultural drama as it has been played for fifty thousand 
years. It has never varied from the stereotyped formula. 
Generations have come upon the stage, have spoken their 
little lines, performed their little stunts, and made their exits. 

To plow, to sow, and to reap, has been for centuries the 
agricultural counterpart of Faith, Hope and Charity. With 
Faith our fathers plowed, with high Hope they sowed, and 
trusted to the Charity of nature to reap. They plowed the 
best they could, they sowed their seed, hoping for the best, 
and then trusted to the sun and the fickle rain to bring the 
harvest. 

In all the wide field of literature we find little or nothing 
of tillage — of the effort to assist nature in her wonderful work. 
Even in the parable of the sower, representing a condition of 
scarce two thousand years ago, there is no reference to the 
preparation of the seed bed nor after cultivation: "Some seed 
fell on stony ground where it had no depth of earth, and im- 
mediately it sprang up because it had no depth of earth; 
but when the sun was up it was scorched, and because it had 
no root it withered away; and some fell among thorns, and 
the thorns grew up and choked it, and it yielded no fruit; 
and others fell on good ground and did yield fruit and sprang 
up and increased and brought forth — some thirty, some sixty, 
and some one hundred-fold." 

Tillage, the scientific treatment of the soil, is of very 
recent origin. It came with the passing of the old regime — 
the regime of the "man with the hoe." To the ancient agricul- 
tural Trinity, to plow, to sow, and to reap, has been added 
"to till" — these three, and a fourth, and the greatest of these 
is — "to till." 

Old Art But New Science 

From the time of Adam and the Garden of Eden, the 
growing of crops has been the chief industry of the human 
race. And during all centuries, soil culture in some form 
has been considered necessary to secure reliable returns in 
grain and fruit. Through the slow process of experience and 
the invention from time to time of improved implements. 



58 CampheU's Soil Culture Primer 

better methods have gradually come into use. It is but 
recently, however, that the education of the farmer in the 
art and science of soil culture has been seriously considered. 
It can be truly said, therefore, that soil culture is one of the 
oldest arts and one of the most recent of sciences. One of 
the latest developments in the science of soil culture, and one 
that opens up great possibilities to the farmers in the socalled 
semi-arid regions of the world where the precipitation averages 
less than twenty-five inches per annum, is the process known 
as "summer tillage." 

Encounters Opposition 

Although the principles of summer tillage have been 
demonstrated to be sound, and although the practice, where 
the details of the theory have been carefully carried out, has 
been successful for a number of years, yet it is very imperfectly 
understood by the average farmer of today. The theory and 
practice of summer tillage, like most new things, met with 
prompt disapproval and determined opposition. The new 
cult was met with predictions of disappointment and crop 
failure, not to mention dire prophesies of an early depletion 
of soil fertility. "The theory is all wrong," said the agricul- 
tural authorities, — "you can get better results from crop 
rotation." But in spite of the opposition and the adverse 
criticism, one important fact remained clear — good crops 
obtained by summer tillage beside total failures under the 
old system. Why this difference under identical conditions of 
soil, climate and rainfall? What is the logical, the scientific 
conclusion? No fertilizers have been used — it must be the 
result of tillage. 

Precise Knowledge Essential 

In this book we give you the results of twenty-five years 
of practical work in the fields; it is the vital link in the entire 
chain of scientific soil culture in the semi-arid regions of the 
world. We urge you, therefore, to study the following pages 
with extreme care, that you may not only fully comprehend 
the principles involved, but note and remember every detail 
of the process, for your success with summer tillage depends 
upon the preciseness with which you carry out the minute 
details of your work. 

The Fallow Field 

The belief that cultivated land needed an occasional rest 
was doubtless responsible for the practice of "summer fallow " — 



CampbeWs Soil Culture Primer 59 

a practice that is nearly as ancient as agriculture itself, and 
which is still followed by the non-progressive farmers in every 
community. 

The fallow field was a familiar division of the old time 
farm and the manner of treatment given this fallow field was 
a pretty good index of the disposition and intelligence of the 
farmer. But do not get the idea that this practice was con- 
fined to "old fogies" or to the less intelligent farmers in the 
community. On the contrary, it was taught by the agricultural 
experts and in many agricultural bulletins you may still find 
"summer fallow" in the regular schedule of crop rotation. 

The Rest Theory 

The practice of summer fallow varies, not only with the 
disposition and intelligence of the individual farmer, but with 
the custom of the community. Here is a farmer who is con- 
vinced that his land is tired and needs a period of rest, so he 
allows his field a complete vacation — abandons it for a year 
or two to a riot of weeds and native grass; here is another, a 
shade more thrifty who lets a field lie fallow but uses it as a 
pasture for his sheep and young cattle. The grass and weeds 
are therefore kept closely cropped; here is another who has a 
field infected with sorrel, or some other persistent weed, being 
thrifty and something of a thinker as well, he not only pastures 
his fallow field, but plows it in midsummer to destroy the 
obnoxious weeds by exposing their roots to the summer sun 
before they have time to seed. His neighbor did the same, 
but his field had not been pastured, consequently a rank 
growth of weeds was turned under before they had time to 
seed. The result was a slightly increased yield in the next 
year's crop in both cases. The conclusions, however, regarding 
the cause of this increased yield were totally different. The 
first one concluded that the result was due to the rest given 
the land and the further fact that grass and weeds were kept 
down. The other was sure that the result was owing to the 
turning under of the crop of weeds — that this acted as just 
that much manure and the increased yield was due to this 
natural fertilizer. 

A Modern Definition 

Thus it will be seen that the rest theory became coupled 
with the theory of weed fertilization in the practice of summer 
fallow. No one seemed to realize that weeds, being voracious 
feeders, take more from the soil while growing, than they 
can possibly give back. No one seemed to remember that the 



60 Campbell's Soil Culture Primer 

principle of compensation — that you can't get something for 
nothing — apphes to soil culture as well as to trade. 

Aside from the eradication of weeds and a slight improve- 
ment in the tilth of the land, owing to a very small addition 
of humus from the weed crop, the old process of summer 
fallow is of little or no value in farm management. In the 
light of modern scientific methods it is difficult to realize how 
the old-time farmer came to believe that a crop of grain was 
harder on his soil than a crop of weeds. But he did believe it, 
and many still believe it, in a sort of unthinking way. Even 
as late as 1906, in a bulletin on crop rotation, issued by the 
agricultural college of South Dakota, Professor Chilcott, com- 
menting on the practice of summer fallow in the experimental 
work, said: "The summer fallow plots are plowed in July 
before the weeds have ripened their seeds, and are plowed 
again with the other plots in the fall. They are given no 
other cultivation during the season." 

A Complete Revolution 

The above may be taken as an authoritative statement 
of the methods of summer fallow up to that date. A complete 
revolution in the methods of handling the fallow field has 
taken place within the last ten years. Clean cultivation, 
intelligently applied, has superseded the old method. This 
practice has become known as summer tillage and is as different 
from summer fallow in object, principle, and practice, as 
success is from failure. 

Claims of Summer Fallow 

Before going further into the subject let us clearly under- 
stand what was claimed for summer fallow and what advantages 
if any, it had over constant cropping. 

The theory that land under cultivation, like a tired work 
animal, needed a period of rest, failed under the test of in- 
vestigation. It was found that an exhausted field under cer- 
tain conditions might require extra food — manure or an 
application of some mineral substance in which the soil seemed 
deficient, in order to secure normal yields, but to allow it to 
rest for the mere sake of resting was on a par with the practice 
of planting potatoes in the moon. We, therefore, will put the 
"rest" theory on the shelf with the other dust-covered curios — 
it is useful only as an index of agricultural progress. 

Destruction of Weeds 

Summer fallow, however, had some value depending on 
the soil conditions. If a field had become foul with noxious 



CampheU's Soil Culture Primer 61 

weeds, a plowing in midsummer before the growth had time 
to mature would make the cultivation of the next year's crop 
a much easier task. The yield was likely to be somewhat 
greater because of the destruction in mid-season of all plant 
growth, resulting in a slight accumulation of plant food in the 
soil. If the summer plowing was timely and had been well 
done, it would, perhaps, result in a larger and better distributed 
supply of moisture in the subsoil. 

Other Fancied Advantages 

Crop-sick land doubtless was benefited to some extent by 
the summer fallow. The change in plant growth and the 
exposure to the elements would naturally assist in clearing the 
soil of toxic poisons. The theory that the old practice of 
turning under a crop of weeds benefits the land by adding 
plant food is, to say the least, questionable. That it adds a 
slight amount of humus to the soil may be true, but with 
most soils the game is not worth the candle. 

We, therefore, will pass to the discussion of summer 
tillage, a process totally different from summer fallow, but 
which, owing to a lack of definite knowledge of the principles 
involved, is often confused with summer fallow, many careless 
writers using the terms interchangeably. The student of 
scientific tillage is, therefore, cautioned to scan carefully 
whatever he reads about summer fallow and summer tillage, 
keeping in mind always the radical difference. 

A New Departure 

Summer tillage is a new departure in the process of soil 
culture. It consists of a combination of certain kinds of work, 
under certain soil and climatic conditions, and at certain 
opportune seasons of the year. The one object in view is an 
increased crop yield, to be brought about through conserva- 
tion, regulation and control of the water content of the soil, 
and the maintenance of a soil condition favorable to the 
liberation of natural plant food. This condition is brought 
about by the regulation of air and moisture in the soil, and to 
some extent the temperature, by thorough and timely cultiva- 
tion. 

While the essential scientific principles underlying the 
theories of summer tillage are old, their application is com- 
paratively new. Coming, as it did, in response to the call of 
the semi-arid west, the prevailing idea is that summer tillage 
applies only to the regions of insufficient and unreliable rain- 
fall. Although its application to the conditions of the more 



62 Campbell's Soil Culture Primer 

humid sections has not been fully proved, yet from results of 
the application of the principles in the semi-arid sections it 
seems reasonable to predict that the practice will prove of 
great value under any and all conditions of soil and climate, 
especially where fertility has become depleted. 

Objects of Summer Tillage 

That the reader may observe and understand the wide 
difference between summer fallow and summer tillage we will 
state briefly the objects sought to be attained by the latter. 
First, an increased yield, far above what is considered a good 
crop, not only every second year, as is popularly supposed, 
but when the system has once been applied and the moisture 
of the soil and subsoil got under control, a bumper crop may 
be expected each year as long as the water content can be 
kept at the optimum, providing always, that the work in the 
preparation and tillage of the soil is properly done. Second, 
the insurance of the crop against failure through drouth. 
Summer tillage, when properly carried out, under reasonably 
favorable conditions is an absolute guaranty against crop 
failure in drouthy seasons. This is brought about by the 
storage in the soil of a large amount of the annual precipitation, 
which is so held that it is made available, not only to the 
plant when needed, but becomes so thoroughly charged with 
plant food in solution, that it is found possible to carry a 
crop through a long period of drouth with much less water 
than would otherwise be required. 

Essential Conditions 

The foregoing are the primal objects of summer tillage, 
but these objects cannot be attained by haphazard methods. 
There are certain conditions that must be carefully observed 
and their meaning understood, if good results are to be secured. 
The storing and conservation of water is of vital importance, 
yet the kind of cultivation and the specific conditions of the 
soil at the time of cultivation are also important and must 
be watched. The work must be carefully and timely done if 
the phenomenally large yields are to be obtained. 

The persistent destruction of weeds is a condition that 
must be insisted upon, for we have learned by experience that 
even small weeds are great drinkers and pump the water out 
of the soil wonderfully fast. Therefore, a summer tilled field 
must be kept absolutely clear of weeds at all times. 



Campbell's Soil Cidture Primer 63 

Increases Soil Fertility 

The first and most important result from summer tillage 
is the release of the natural fertility of the soil — the inorganic 
elements — and to render it available as plant food. This is 
brought about by various chemical agencies that act with 
the greatest efficiency when the soil carries a certain percent 
of both moisture and air. Just what the percent is that gives 
the best results is not accurately known — it doubtless varies 
with the texture of the soil — but experience indicates that the 
water content should be near the highest limit of capillarity 
and that there should be sufficient air to supply the oxygen 
needed by the roots in the process of cell formation. To secure 
this ideal combination of air and water, the soil composing the 
seed and root beds should be made fine and firm with a loose 
mulch covering the surface to prevent loss of moisture by 
evaporation, for the moment the moisture content is reduced, 
either by direct evaporation from the surface, or by transpira- 
tion through weeds the delicate balance is disturbed and the 
chemical action in the soil is checked in the same proportion. 

A second result of summer tillage, in fact a direct corollary 
of the first, is a marked decrease in the amount of water 
necessary to produce a pound of dry matter. The amount is 
less owing to a decrease in the demand of the growing crop, 
due to an increase in available fertility. 

Not Necessary Every Alternate Year 

It must be thoroughly understood that in order to obtain 
the largest annual profits from your fields, summer tilling is 
by no means advisable each and every alternate year, except 
where the average annual rainfall is less than fifteen inches, 
and even then with certain soils and a well distributed rainfall 
it is possible to store the available moisture, so that two and 
possibly three crops may be grown in succession. This will 
depend, however, on the care with which you handle your soil 
and the persistency with which you conserve the moisture. 
Your guide in this matter should be always the condition of 
your soil, and the amount of soil water you have in reserve 
at the close of each crop season. With a close consideration 
of these two points you can easily determine whether there 
is a sufficient amount of moisture in reserve and whether the 
land is in condition to grow another good crop, or whether it 
should be summer tilled again. 

The First Steps 

It is said that the education of a child should begin with 
his grandfather; so it is with a field to be summer tilled. The 



64 Campbell's Soil Culture Primer 

work should begin the year before. As a general proposition 
summer tillage cannot be carried out in its entirety and the 
best results obtained until one or two crops have been grown. 
The first step — a thorough double disking of the ground — 
should be done as soon after the crop is removed as possible. 
The advantages of double disking the land immediately after 
the crop is removed, especially if it be a crop of small grain, 
are four-fold: 

First, by forming a surface mulch it conserves the moisture 
already in the soil. 

Second, by presenting a loose surface the autumn rains 
are more readily absorbed and retained by the subsoil. 

Third, the stirring of the surface soil hastens the germina- 
tion of all weed seeds and volunteer grain, the young growth 
of which should be destroyed by subsequent cultivation. 

Fourth, the condition of the soil as to water content, 
thus produced, together with the high soil temperature of 
late summer, favors bacterial activity, and brings about a 
chemical action that results in the liberation of inorganic 
plant food. 

No Time Can Be Lost 

No time should be lost in beginning the work. In the 
case of a field of small grain the disk should follow the binder, 
for what moisture is left in the ground will evaporate very 
quickly after the shading efi'ect of the standing crop is removed 
and the hot rays of the sun are allowed to beat upon the 
compact surface and dead stubble. It is very important to 
conserve this moisture. The loosening of the surface by the 
disk checks the upward movement of the soil moisture, causing 
it to accumulate in the firm soil just beneath the mulch. 
This regulation of the water content not only increases chem- 
ical action in the soil, but also increases the capacity of the 
soil for absorbing and retaining subsequent rainfall. 

The Little Things Count 

The importance of this early fall work is governed largely 
by local climatic conditions and the amount of annual precipita- 
tion that may be expected. In sections of the country where 
the average annual rainfall is less than eighteen inches, it 
should never be omitted, as the harvest may be followed by 
a drouthy year, and the moisture that may be conserved by 
this early work may be just enough when added to the regular 
precipitation to carry the crop to maturity, when without it — 
although the amount may be small — the crop would fail. 



CampheU's Soil Culture Primer 65 

It is often the little and not the big things that make for 
success or failure. It must be remembered that plant growth 
continues just as long as there is available moisture at hand — 
not that moisture is the only necessary element, but all other 
elements are worthless without it. 

How to Begin 

As stated in the preceding paragraph, the first step in 
summer tillage, after a crop has been removed, is to double 
disk the land. If the crop on the field to be summer tilled 
was small grain, the disk breaks up the surface into small 
lumps and mixes the stubble with the loosened soil, forming 
a mulch. The efficiency is not destroyed by subsequent rains 
because the stubble, by keeping the mulch from becoming 
compact, prevents the heavy rains from completely reestab- 
lishing capillary connection with the moist under soil and 
consequent rapid upward movement of moisture and evapora- 
tion. 

Destroy Weeds and Volunteer Grain 

When heavy autumn rains follow harvest, causing ideal 
growing conditions, weeds and volunteer grain will spring up 
wherever the seed has fallen. This growth can usually be 
destroyed on the land that has been double disked, by the 
common steel harrow if the work is done quickly, before the 
grain and weeds become too well rooted. 

No time should be lost in getting into the field as soon 
as the weeds appear above the ground. Here a "stitch in 
time saves nine," for weeds are not only great drinkers, and 
when still very young, use an immense amount of water, but 
every day they are left unmolested they become more firmly 
rooted and are the harder to eradicate. A growing weed is 
the most expensive thing that can be kept about a farm. 



66 CampheU's Soil Culture Primer 

CHAPTER 10 
STORAGE OF MOISTURE 

The beginning and the end of summer tillage is the con- 
servation of moisture — the storing of water in the soil as in 
a reservoir. The old-time irrigator stored the surplus water 
of running streams in an artificial reservoir and turned it onto 
his fields when he thought his crops needed it. The modern 
scientific farmer stores the rainfall in the soil and holds it 
there ever ready for the growing crop when it is needed. 
There is another difference; the old-time irrigator loses half 
of his stored water by evaporation from the surface of his 
reservoir and in the process of applying it to his field. But 
in summer tillage very little moisture is lost by evaporation, 
and, as we shall see, the water, while stored in the soil, is not 
idle, but is busy dissolving inorganic matter for the use of 
the plants. 

The Soil as a Reservoir 

That water, whether it be applied artificially by irrigation 
or falls in the form of rain and snow, can be stored in the soil 
and held there for the use of a crop, is a new proposition in 
agriculture. It is so new that only a very few of the world's 
experts in soil culture understand the methods by which it is 
done, or appreciate the far-reaching effect of the discovery. 
In fact, the general opinion is that it cannot be done. But 
in the face of this opinion it is being done by thousands of 
experimenters and practical farmers in the so-called dry 
farming sections and in the irrigated districts every year. 
In fact, it has been demonstrated, that the best results in the 
growing of fruit orchards and cultural crops in the irrigated 
sections of the arid west are obtained from one irrigation a 
year. The universal success of summer tillage methods applied 
to irrigated lands is completely revolutionizing the method of 
the application of water with the result that the irrigable 
acreage of the world will be increased four-fold. This is also 
true of the semi-arid area of the world. 

What to Do in the Spring 

Now, let us go over the process of summer tillage step 
by step, seeing that everything is done that should be done, 
and learning, if possible, the reasons for the various steps. 
The field designed for summer tillage, that has been disked 
in the autumn and kept clear of weeds, as we have outlined. 



Campbell's Soil Culture Primer 67 

will have absorbed a great part of the autumn and winter 
rains, and if there has been a fall of snow, that too will soak 
into the soil at the opening of spring. The first problem, then, 
is to hold this water in the soil — to prevent its evaporation 
during the warm and windy days of early spring. How can 
this be done? Put a lid on as soon as possible. Get onto the 
field with a disk harrow as soon as the condition of the top soil 
will permit. Don't wait until it is dry — get on while it is yet 
wet, and double disk it; break up the surface crust, if one has 
formed, and put in its place a mulch of small clods — not a 
dust mulch, for that would be fatal, especially where high 
winds are likely to prevail during the spring months. You 
want a coarse mulch — one that will not blow, therefore, disk 
the ground when it is sufficiently wet to roll up into little balls 
from the size of a pea to that of a walnut. 

Depth of Disking 

The depth to which the disk should cut depends upon 
the condition of the surface. If the surface be already loose, 
set the disks so they will run light and cut shallow. If there 
is a crust formed and the surface is getting somewhat dry, set 
them at a greater angle and cut deeper — deep enough to turn 
up the moist soil. Be sure to double disk by lapping your 
implement one-half. The reason for doing this on land to 
be summer tilled is that it leaves the surface comparatively 
level. If you use the single disk, there is left, after each round, 
a back furrow where the outside disks throw up the dirt that 
is removed from the center, and an open furrow formed by 
the action of the inside disks. Here, in the absence of a 
mulch, evaporation will take place rapidly and a crust will 
quickly form. This defect the double disking corrects, leaving 
the surface with a uniform mulch, level but slightly ridged 
and cloddy. This is what is desired. If conditions will permit 
it, a shallow mulch is best for the reason that the rainfall will 
more readily soak into it, and then, too, the weather being 
cool and the evaporation slight, a deep mulch is unnecessary. 

After the First Rains 

When the disked surface has become packed by the first 
rains, it should be loosened at once with an Acme, or a spike- 
tooth harrow. This work should be done without delay, 
while the ground is yet moist, because a mulch made from wet 
soil will not drift, and for the further reason, that in this con- 
dition a much lighter mulch will do — and the lighter the 
mulch at this time of the year, the better, because, as above 



68 CampheU's Soil Culture Primer 

stated, the rainfall will be absorbed more readily than by a 
deep and fine dust mulch. The reason for this is, that moist 
soil has a greater attraction for water than has dry soil. So, 
the nearer to the surface we can keep the moist earth and still 
protect it from evaporation, the more readily will it take in 
the subsequent rainfall. If the soil can be kept moist near 
the surface, as soon as the mulch becomes wet, the water will 
percolate very rapidly down to the subsoil. Thus, shower 
after shower rray be quickly stored if the conditions are just 
right. After every rain, therefore, that tends to pack the 
surface, the field should be gone over with a light implement 
to restore the mulch and bottle up the moisture. When once 
the mulch is established, the moisture keeps moving down into 
the subsoil and is there held fast by capillarity. Rainfall after 
rainfall may thus be stored and kept so long as the surface is 
kept sealed with a proper mulch to prevent evaporation. 

Weeds Must be Kept Down 

As soon as the sun gets warm and the rains come, the 
weeds will start up. They come without bidding and need no 
cultivation to grow. They must be met and destroyed before 
they can take root. Various devices may be used for this 
purpose. When the weeds are young and tender, most any 
light harrow will do the business; but should they get a start, 
a disk harrow may be necessary to kill them. But weeds 
should never be allowed to get a start. They are not only the 
most inveterate drinkers in the world, but, while they are 
using up the precious moisture you are trying to store in the 
soil, they are also taking up a large percent of the plant food 
that has been liberated — and this you want to keep for your 
coming crop. An idea seems to prevail that weeds do not 
exhaust the fertility of the soil — that in some way they do 
the land good if you let them grow and plow them under. 
This is just like lifting yourself over the fence with your boot- 
straps. Keep every weed out of your summer tilled field. It 
will do you no good to keep the lid on to prevent evaporation 
if you allow a million little pumps to pull the moisture out 
through the lid. That lid must be tight — and you must see 
that it is kept tight. 

When to Plow 

The time to plow your summer tilled land is determined 
by conditions. In the northern spring wheat country plowing 
should be started in time to be finished before harvest begins. 
In the winter wheat belt of Nebraska and Kansas, the plowing 



CampheU's Soil Culture Primer 69 

should be done in early July, and in Oklahoma and Texas in 
August. If the land is to be planted to either spring grain, 
or cultivated crops, the plowing may be delayed longer than 
if intended for autumn sown grain. But plowing should never 
be delayed a moment if it becomes necessary to keep the weeds 
down. Weeds must be kept down at all hazards, if it cannot 
be done with the harrow — you must plow. 

Depth of Plowing 

In case the land that has been summer tilled is old land, 
plow from six to seven inches deep. Experience has proven 
that it is unwise to plow to a greater depth than can be reached 
with a subsurface packer. And where the soil is fairly heavy — 
a clay or a clay loam — it is difficult to pack the plowed ground 
thoroughly to a greater depth than seven inches. And if you 
have held the season's moisture in the soil, this will be suf- 
ficiently deep, for your subsoil will be moist and will afford 
the growing plant an ideal root bed — firm and rich in plant 
food. A sandy soil may be plowed deeper, if plowed when 
moist. This is true also of the soil of the semi-arid west, 
known as volcanic ash. 

Plowing Must be Packed 

In mid-summer, when high temperatures prevail, evapora- 
tion from the surface is very rapid, therefore, the plowing on 
summer tilled land should be packed at once with a subsurface 
packer. The dryer the soil gets before packing, the less 
effective will be the work. There should be no delay. Where 
motor power is used, the packer should follow the plows in 
one operation. Where horse power is used the plowed field 
should be packed before leaving at noon and at night. Whether 
a harrow should follow the subsurface packer should be deter- 
mined by conditions. Generally, the subsurface packer, while 
firming the under portion of the plowed ground leaves the 
surface in a pretty fair condition to resist evaporation, and a 
harrow may or may not improve it. A rain, however, that is 
sufficiently heavy to pack the surface should be immediately 
followed by the harrow to loosen up the surface just the same 
as before plowing. 

Between Plowing and Seeding 

Between the time of plowing summer tilled land and the 
time of seeding either to a fall or a spring crop, the same care 
must be exercised as before plowing to keep the weeds out 
and a satisfactory mulch on the surface. Remember that the 



70 CampheU's Soil Culture Primer 

lid must be kept on or the moisture so carefully stored during 
the fore part of the season will escape. And right here, eternal 
vigilance is the price of success. It is the conservation of the 
water that you are after, and the longer you can hold it there 
and the more evenly balanced you can get the content of 
water and air m the soil, the greater will be your crop yields 
the coming year. Remember also, that while you are keeping 
your field bare and holding the capillary moisture up to the 
mulch, the summer heat and the microscopic organisms that 
inhabit the soil and flourish under these conditions are prepar- 
ing the food for your next year's crop. Your field, though bare 
on the surface, is literally swarming with life beneath the 
mulch. You are not only storing up the sun's rays but the 
processes going on beneath the surface are unlocking the 
store rooms of the inner earth. 

Summer Tilling New Ground 

In summer tilling new ground the process varies some- 
what. If the sod can be turned in the fall, well and good; 
if not, it must be turned as early as possible in the spring. 
Plow it while moist and to a depth of from three to three and 
one-half inches, turning the furrow slice completely over so 
that the grass may rest against the moist soil beneath. Follow 
the plow with a roller or a subsurface packer to crush the 
furrow slice firmly down, leaving the surface as level as possible. 
Here is where good plowing is essential. The furrows should 
be straight and free from kinks. If a surface roller is used, it 
should be hauled in the opposite direction to the progress of 
the plow. This will have a tendency to smooth out all sod 
kinks and crowd each furrow slice flat. Follow the roller, or 
the packer, with a disk harrow set to cut an inch or so into the 
inverted furrow slice. Never allow the disk to cut through. 
This will give you a mulch on the surface and fill all openings 
between the furrow slices. Sometimes it may be good form to 
follow the disk with a float, or smoothing harrow, but this is 
not usually good practice where the soil is likely to blow or 
drift when pulverized. 

Why We Do This 

The reasons for the above treatment are first — to rot the 
sod by pressing it against the moist subsurface; and, second — 
to form a mulch to prevent the evaporation of soil moisture. 
The reason why we break only three inches deep is because 
this is about the limit of the grass roots, and a three inch 
furrow will turn over and lie flat, leaving at the same time 



Campbell's Soil Culture Primer 



71 



enough soil exposed to the air to form an ideal mulch to protect 
the moisture in the soil beneath. At the same time this three 
inch coating will absorb and transmit to the under soil, which 
will be always moist, any ordinary rainfall during the season. 
Should weeds start up they must be handled just as they are 
handled on old ground. When a rain settles the mulch, it 
must be restored with a light harrowing, as on older ground. 
By midsummer, unless the season be excessively dry, the sod 
will have completely rotted and your field is ready to be plowed 
and prepared for either a fall or a spring crop. This plowing 
should be not more than five inches deep, and should be 
followed by the packer the same as in the treatment of old 
ground.. 




0r*. ' fflv 





Fig. XV 

Summer Tilled Field. Note the Soil Mulch and Absence of Weeds 



72 Campbell's Soil Culture Primer 

CHAPTER 11 

CONSERVATION OF SOIL MOISTURE 

Do Crops Need Rain? 

That crops can be grown and brought to maturity on 
moisture stored in the soil at the time of planting has been 
demonstrated by Professor Alway of the Agricultural College 
of Nebraska in a most interesting and conclusive manner. 
Six cylinders of galvanized iron were filled with soil as near as 
possible in its natural condition. Three cylinders contained 
soil from the eastern, and three from the western part of 
Nebraska. Water was added until seepage began, when it 
was allowed to drain away until only capillary water remained. 
The cylinders were then closed, except at the surface, and 
sprouted grains of spring wheat were planted in the moist soil 
and an inch of dry soil added to form a mulch to prevent 
evaporation. The cylinders were placed in a green-house, the 
atmosphere of which was kept as dry as possible. No more 
water was added. The wheat grew, developed and ripened 
normally. The first heads were ripe in 132 days after planting 
and the last in 143 days. The cylinders of soil from the semi- 
arid section cf the state produced 37.8 grams of straw and 
twenty-nine heads containing 415 kernels which weighed 11.18 
grams. The three cylinders of soil from the eastern or humid 
section of the state produced 11.2 grams of straw and thirteen 
heads, containing 114 kernels, weighing three grams. 

This experiment demonstrated conclusively two things; 
first, that enough water can be stored in six feet of ordinary 
soil and held there by a surface mulch for the use of a crop 
from planting to maturity; second, that the soil from the 
semi-arid sections of the country is much richer in plant food 
and will produce greater yields (in this case three times the 
yield), than the soils of the humid sections, under identical 
or similar conditions. 

Storage Capacity of Soils 

The capacity of the soil for absorbing and retaining 
moisture depends on its physical structure — the finer the 
texture, the greater the surface area, and, consequently, the 
greater the water holding capacity. In this regard very little 
accurate data has been gathered for the reason that until 
within the last few years it was regarded as unessential. But 
from the tests that have been made, the average of field soils 
is about 1.5 inches of water per foot of soil. Now, if this ratio 



Campbell's Soil Culture Primer 73 

will continue down ten feet, we can store twenty-five inches 
of rainfall, or the available moisture of two years precipitation 
on the semi-arid plains. The theory that in the average soils 
of the plains two or even three years rainfall may be stored 
in the soil seems to be proved by the universal experience of 
all the demonstrators and experimenters from the Saskatchewan 
river to the Rio Grande. Atkinson, of Montana, found that 
soil at a depth of nine feet, which contained 7.7 percent of 
capillary moisture in the fall, in the spring was found to con- 
tain 11,5 percent, and that after carrying it through the summer 
by careful methods of cultivation it still showed eleven percent. 
Widtsoe states that investigations in Utah show that of the 
water and snow% which fell during the winter, as high as 
ninety-five and a half percent was found stored in the first 
eight feet of the soil at the beginning of the growing season. 
Burr, of the North Platte, Nebraska, experiment station, has 
demonstrated that fully one-half of the spi'ing and summer 
rainfall may be stored in the first six feet of soil. It may be 
regarded as clearly proven that from fifty to ninety percent of 
the rainfall in the semi-arid sections of the world may be 
stored in the soil and kept there for the use of the growing 
crops. 

How Soil Moisture Is Held 

It must be understood that water is held in the soil in the 
form of thin films around each particle, and not in the spaces. 
Therefore, it will be noticed that the soil grains where the very 
points of the little feeders come in contact with them show no 
water, the film of water having been so reduced by the drinking 
or sucking in of the solution by the very tip of the feeder. As 
the film is diminished around these grains the next soil grain 
gives off a percent of its moisture to even up, thus the movement 
of moisture goes on from one soil grain to the other, in an effort 
seemingly to keep up an even tension, or thickness of the 
films throughout the moist portion of the soil. 

Not only does the moisture move laterally in the soil 
towards the points of these little feeders, but upward from 
below, as the demand of the plant increases, either from its 
increased size or from a greater evaporation from the leaf, 
caused by excessive heat. At such times these little feeders 
are taxed to their limit to gather in the moisture fast enough 
to prevent the wilting of the leaves. Under such condition 
the moisture in the upper layers becomes diminished and the 
supply must come from below. 



74 



CampheU's Soil Culture Primer 



How Soil Moisture Moves 

Figure 16 represents a perpendicular cross-section of soil 
in various stages of saturation. Column A represents the condi- 
tion of the soil immediately after a heavy rain. The moisture is 
represented by the dark part completely surrounding the soil 
grains, below is the dry soil with the interspaces filled with 
air, represented by the white. In column B the water has 
percolated down some distance, leaving the upper soil grains 
covered with a film of capillary water and the inter-spaces 







FiG. XVI 
Getting Water Into the Soil 



filled with air. In column C the entire soil section is carrying 
the highest limit of capillary moisture and the proper content 
of air — the ideal condition of the seed and root beds. 

Assuming that the top of column C is exposed to the sun's 
rays and the wind, and that no loose soil mulch covers the 
surface to protect the moisture and to keep the top of the moist 
soil cool enough so no steam or vapor may be produced, 
under this exposed condition the sun will soon dry the surface 



Campbell's Soil Culture Primer 75 

particles by transforming these films of water into steam, or 
vapor, thus causing the next soil grain below to reduce its 
film of water by the natural tendency to supply the one above, 
or the natural tendency of the upper grains to rob the lower 
grains as the moisture is lost by evaporation from the surface. 
This process, if not checked by cultivation, will go on until 
the entire capillary water has been drawn out of the soil. 

Now we will assum.e that we have a loose mulch over the 
surface of column C, to a depth of about three inches. This 
would make it impossible for the moisture to move up beyond 
the firm point. If this mulch is cultivated sufficiently often 
to keep a crust from forming at the top of the firm soil, an 
ideal condition will exist, for the oxidizing and nitrifying 
processes to go on, which dissolves and liberates the plant 
food. 

Something New 

We already know how water is held in the soil — we are 
familiar with the laws of capillary action; we know that the 
plant takes its food from the soil in solution, and that when- 
ever there is a scarcity of moisture, growth ceases. We have 
learned, too, how to catch and hold this moisture in the soil 
for the use of the plant; we know^ how to form and maintain 
a mulch to bottle up the stored rainfall; we know what the 
plant requires in the nature of a seed and root bed — all these 
things must be looked after in summer tilling a field. The 
primal object of summer tillage was to conserve moisture, to 
store two years precipitation in the ground for the benefit of 
one crop. This was the original idea. It is still a reason for 
summer tillage, but not the whole nor the most important 
reason — there is another and a greater reason, but it rests 
on the first like a building on its foundation. This other 
reason is the liberation of plant food. 

Transpiration and Fertility 

We have learned that the water in the soil is both food 
and drink for the plants; that if there is a lack of plant food in 
the soil for the water to dissolve there will be little growth; 
that when the soil solution is weak, the plant in trying to get 
enough food will use an enormous amount of water; that 
when the solution is stronger less water is used by the plant 
in production of a unit of dry matter. We have learned that 
there is a direct relation between fertility of the soil and the 
amount of water transpired by the growing crop the richer 
the soil solution the less water used. We know that ex- 
perimenters working in different parts of the world found that 



76 Campbell's Soil Culture Primer 

summer tilling the soil produced the same effect on the amount 
of water required to produce a unit of dry matter, as the 
application of fertilizers. The conclusion is inevitable — summer 
tilling releases the plant food and renders it available for the 
growing crops. How is this brought about? It is brought 
about by the action of heat and sunlight when the moisture 
content of the soil is just right. It is brought about as a 
result of conditions favorable to bacterial action. Doubtless, 
each and all of these factors contribute to the result. The 
proper balance of air and water in the soil, together with the 
heat of summer produce conditions favorable to bacterial life, 
and this life is a necessary link in the process of rendering the 
inorganic substances of the soil available for the plant. It is 
possible, also, that the sunlight exerts a chemical effect on the 
soil substances favorable to the coming crops. Professor 
Montgomery found that the hotter the season the greater 
amount of water a plant will use to produce a unit of dry 
matter. He found that in 1910 it required two hundred-fifty 
pounds of water to produce one pound of dry matter (corn), 
but in 1911, a much hotter season, it required three hundred 
forty-five pounds under similar physical conditions, the tem- 
perature alone excepted. Now. why was this? Owing to the 
greatly increased evaporation from the leaf, by the excessive 
heat, the moisture at the top of the soil, was more quickly 
reduced, and the supply drawn from a lower strata of the soil, 
where the temperature was not sufficiently high to bring about 
adequate chemical action, consequently the moving of the 
water from this lower zone, carrying a much lower percent 
of soluble plant food, produced a like lower percent of growth. 
This conclusion is substantiated by figures of Professor Widtsoe, 
who found that where the transpiration from the plant was 
slower, the growth was greater from the same amount of water; 
thus, again indicating the necessity of the water being carried 
in the upper part of the soil, where the proper degree of heat 
obtained for a longer period, producing the high percent of 
soluble plant food as well as an increased percent of nitrates. 
A Plausible Theory 

Investigations along the lines of tillage, together with 
our knowledge of the conditions under which plant life thrives, 
all point to a theory that may account scientifically for the 
wonderful results obtained from summer tillage. Old prin- 
ciples that have played their part in the growth of plants 
since the cultivation of the Garden of Eden — principles that 
have never been fully understood nor regarded as of any im- 
portance, are now considered from an entirely new viewpoint. 



CampheU's Soil Culture Primer 



77 



This is the theory. When the capillary water is held in close 
contact with the soil particles of the root bed under the proper 
temperature, the soil at the same time being supplied with 
oxygen from a free circulation of atmospheric air, a chemical 
action takes place which liberates food by dissolving the in- 
organic elements of the soil and forming soil solutions. The 
longer the moisture under favorable conditions remains around 
the same particles of soil, the greater (to a certain extent) 
becomes the percent of soluble plant food in solution. When 
this capillary moisture, impregnated with an increased percent 
of plant food, is taken in by the minute rootlets or feedei-s — the 
mouths of the plants — and is digested and assimilated, growth 
is of necessity more rapid and vigorous, than when the moisture 
has remained a less period adjacent to the soil grains, for the 
simple reason that the dissolving elements have not had time 
to act. Therefore, it is quite reasonable to conclude that less 
actual water is required to grow a crop where the moisture 
has been held in the soil for a considerable length of time by 
summer tillage, than under ordinary conditions where the 
water is allowed to continuously escape through weeds or by 
direct evaporation. In other words, a greater gi'owth and a 
larger crop yield may be obtained with the same amount of 
available water. 

Demonstration at Sligo, Colorado 

A most interesting demonstration tending to prove the 
above theory was made on the farm of Mr. S. G. Morgan near 
Sligo, Colorado, during the summer and fall of 1911. The 
record of the rainfall kept by Mr. Morgan for the year 1911, 
is as follows: 

DATE AND AMOUNT OF PRECIPITATION AT SLIGO, COLORADO, 1911 



April 

May 

May 

May 

June 

July 

Aug. 

Aug. 

Sept. 

Oct. 



29 75 inches 

10 53 inches 

28 57 inches 

29 25 inches 

16 70 inches 

13 1.53 inches 

9 45 inches 

11 25 inches 

2 1.19 inches 

1 25 inches 



April 

May 

June 

June 

July 

July 

July 

July 

Aug. 

Oct. 



30 03 inches 

19 05 inches 

15 03 inches 

21 10 inches 

2 06 inches 

3 07 inches 

16 07 inches 

19 20 inches 

5 15 inches 

5 20 inches 



Am't available 6.79 inches 



Am't available .96 inches 
6.79 inches 



Total 7.75 inches 



78 CamphelVs Soil Culture Primer 

In observing the above record it must be remembered 
that the precipitation at any one time must exceed one-fifth 
of an inch, or no benefits can be derived from the shower in 
the way of increased storage of water. It is also a known 
fact that a shower which is sufficient to moisten the mulch 
will reduce rather than increase the stored water, because 
the moistened surface tends to draw the moisture from below 
to the surface where it evaporates, a condition which is checked 
only by cultivation and the reformation of a mulch. 

Out of the total precipitation of seven and three-quarter 
inches in twenty-one showers, we find ten showers of one-fifth 
inch or less, aggregating .96 of an inch, leaving about six and 
three-quarter inches from which a percent of each shower, 
eleven in number, could have been stored and retained in the 
soil. With this amount of rainfall, thirty inches of moist soil 
was found in the soil on November 20. 

As there was practically no precipitation from October, 
1910, to April 28, 1911, the records begin April 20. In the 
left hand column we give the dates and amount of rain out 
of which a percent could, with proper tillage, be stored in 
the soil, and in the right hand column the dates and amount 
of precipitation out of which practically no moisture could 
have been stored. 

How the Work was Done 

Mr. Morgan began early in the spring of 1911 to summer 
till thirty acres. Not being supplied with proper tools, he 
was obliged to reduce this to fifteen acres in order to keep 
the weeds out and retain the larger percent of all the moisture 
that fell. The remaining fifteen acres were cultivated there- 
after, but the weeds were not all kept down, thus losing a 
considerable amount of moisture. On August 1, the whole 
thirty acres had just been plowed, packed and harrowed. 
The half that had been well handled was moist to a depth 
of twenty-six inches, while the part that had been less care- 
fully handled showed about fifteen inches of moist soil, no 
part of which carried as high a pei'cent of moisture as was 
carried by the soil of the other field — from right beneath the 
soil mulch down to the very last of the twenty-six inches. 

Planted to Wheat 

On the first and second of September the entire thirty 
acres were seeded to wheat, finishing at noon, the second. 
On the evening of the second, as noted in the table, one and 
one-fifth inches of rain fell; on the fourth the field was har- 
rowed over. Now, note this fact, that with this amount of 



Campbell's Soil Culture Primer 



79 



precipitation and the harrowing the second day after the rain, 
it is fair to conclude that practically the same amount of 
moisture must have been available to the young wheat plants 
in both the well tilled field and the field where the moisture 
was practically lost through the growing weeds before plowing. 
Now, let us see what happened. Cut No. 17 shows four stools 
of wheat, two from the field kept clear of weeds and two from 
the other; A represents twenty-three well developed stalks, or 
stools, of wheat from one grain, while B, which grew in the 
field where weeds exhausted or utilized a large percent of the 
moisture during the summer, shows only six stools. The 
stooling of the single plants in the well cultivated field runs 
from seventeen to twenty-six, while the plants where the 




a b 

Fig. XVII 

Results of the Morgan Demonstration 

moisture was depleted in June and July, produced from three 
to seven stools from each grain. This shows very conclusively 
that the solution available at the roots of the plants in the 
well tilled field carried a much higher per cent of plant food than 
did the solution available in the other part of the field. 
Demonstration at Holdrege 

Similar results were obtained on the Burlington demon- 
stration farm at Holdrege, Nebraska, in 1910. Figure number 
18 shows two stools of wheat gathered November 18, 1910, 
from adjoining fields. Both fields were seeded about the tenth 
of September, one had been summer tilled, but the ot)ier had 



80 



Campbell's Soil Culture Primer 



grown a crop in 1910 and had then been plowed and planted 
to wheat. Fifteen days after seeding a very good rain fell, 
putting the two fields in the same condition so far as water 
content of the seed bed was concerned. The larger stool from 
the summer tilled field, containing sixty-three well developed 
stalks, is not an exceptional sample, but a fair average of the 
field. The smaller stool containing five stalks is also an 
average sample of the best part of the field treated in the 
ordinary manner. 

While it is true that the seed and root bed in the summer 
tilled field was finer and firmer, which was more favorable to 
the rapid growth and development of roots, yet after the rain 



The result rftone grain of wliUt in 49 dayg. Both plantei^ept. 7th. stooU 




Fig. XVIII 
Results of the Holdrege Demonstration 



the last of September, the conditions in this respect would 
have been nearly alike in both fields because of the dissolving 
and settling effect of the rain on the late fitted field. It seems 
that the above facts from practical field results, bear out the 
conclusion that a very much larger growth of plants may be 
obtained from a given amount of water held or confined in 
the soil under proper conditions, than from a larger precipita- 
tion or irrigation under conditions where no attempt is made 
to control the water, which is allowed to move at will in its 
natural course. 



Campbell's Soil Culture Primer 81 

While it is doubtless true that the evaporation from the 
first leaflets, as they made their appearance from the seed in 
each part of the field, were the same, yet in the well tilled 
field in which the higher percent of moisture had been steadily 
held in the soil through the hotter part of the season, there 
was a larger percent of available plant food which was, there- 
fore, taken in by the little rootlets and carried to the plant 
in a richer form, to cause the greatly increased growth and 
stooling. As an illustration, suppose you feed a certain num- 
ber of pigs clear milk from which the butter fat has been taken 
out and, to another similar number the same quantity of milk 
but to which is added corn meal. Which would be expected 
to make the greater growth? 

Results From Summer Tillage 

The results from summer tillage, when properly carried 
out, have been little less than phenomenal. The Nebraska 
substation at North Platte averaged forty-five bushels of 
wheat to the acre for five years in succession, running as 
high as sixty-seven bushels to the acre. On the Burlington 
demonstration farm at Holdrege, Nebraska, fifty-two bushels 
were produced, while one hundred thirty-two bushels of oats 
is the record of a summer tilled field in Alberta. In sections 
of the country subject to periodic drouths, summer tillage is 
an insurance against failure. Even where the rainfall is so 
low that alternate cropping is thought necessary, the yield 
obtained every other year is so much greater than can possibly 
be obtained under the practice of constant cropping that the 
farmer is far ahead of the game and with less work. 

Objections to Summer Tillage 

The objections that have been raised to this method of 
tillage are: First, that it tends to destroy the humus in the 
soil — burn it out, as it were; second, that it is too costly — the 
land must be left idle a part of the time and then it takes too 
much work to keep the weeds out and a mulch on the surface; 
third, that it causes the soil to drift (blow) wherever it is 
exposed to high winds, as it is in the semi-arid west where it 
is recommended by its advocates. Up to date, those holding 
these opinions have been unable to prove their objections to 
be well founded in practice. While there may be something 
in the theory, the objectionable features can be overcome. 

The Humus Idea 

The opponents of summer tillage claim that it will destroy 
the humus of the soil, and if persisted in long enough, put the 



82 Campbell's Soil Culture Primer 

land completely out of business, so far as crop production is 
concerned. But they don't seem to have any demonstrated 
data on which to base their theory. On the other hand, 
Whitney, chief of the United States bureau of soils, says that 
humus is practically indestructible. In the meantime, the 
practice of summer tillage is producing bumper crops in good 
years and fair crops in drouthy years, with no apparent 
disastrous effect on the soil. Just in what way summer tillage 
should differ in its effect on the soil from the clean culture 
given corn, potatoes, or any other hoed crop, is not explained. 
There is little doubt, however, that in summer tillage, as in 
any other method of clean culture, it is necessary to replenish 
the soil with humus-making material if you want to keep the 
fertility of the soil up to the primal limit. 

The Cost Objection 

This objection seems too foolish to need attention, yet 
there are so many who balk right here that a word or two may 
do some good. We have already seen that as a general rule 
where the plan is to crop every alternate year, the yield is 
more than double the annual yield under the constant cropping 
system. Where then, is the loss from allowing the land to 
remain idle? There is none. On the contrary, there is a 
decided gain. But one seeding is necessary and but one 
harvest, and we all know it costs but little more to harvest 
a wheat crop that yields forty bushels to the acre than it does 
to harvest one that averages fifteen bushels. As to the item 
of cultivation, we must add the cost of three diskings and as 
many harrowings as the conditions make necessary. These 
will depend entirely upon the weed growth and the number 
of rains that come during the summer tilling season. The 
comparative cost must be figured out for each individual 
case, and it will differ with the seasons, the soil, and the time 
of the rainfall. 

About the Drifting 

Over a large part of the semi-arid west, especially in 
localities where there is a fine soil exposed to the sweep of the 
wind, if the surface be pulverized by surface rolling, or too 
much harrowing, it is likely to drift badly. This is a serious 
objection to clean culture of any kind, unless the mulch be 
kept in a cloddy condition, or the surface so ridged as to check 
the force of the wind. Here a dust mulch would be fatal to 
any field. If there is any moisture in the subsoil, and if the 
plowed soil be properly packed with a subsurface packer, a 



Campbell's Soil Culture Primer 



83 



mulch can be maintained that will not blow. This has been 
demonstrated beyond a doubt. It is the lifeless soil alone 
that drifts — the fine, powdery stuff that contains no moisture. 
If the moisture line be kept near the surface by packing, there 
will be sufficient hygroscopic moisture given up to the mulch 
to hold it intact. 

The Ridge Theory 

The ridge system of cultivation advocated by the 
Agricultural College of Kansas, will doubtless prevent 
drifting to a great extent. In this system the ground 
is thrown up into ridges with a lister — not plowed — with 
the idea that less rainfall will escape through the run-off than 




Fig. XIX 

Soil Listed to Conserve Moisture and Prevent Drifting 

from level cultivation. When the ridges become dry after a 
rain, they are harrowed down, the surplus dirt falling in the 
furrows, thus covering with a dry mulch the wet soils. Care 
is taken to list the field as near as possible at right angles to 
the direction of the prevailing wind, so that the force of the 
moving air is broken every few feet and at least one-half of 
the surface is perfectly protected. This condition is main- 
tained only in the fall and spring, when the winds are likely 
to do the most damage. Later in the season the ridged 
surface is worked down and the ridges split, if necessary, to 
conquer the weeds and harrowed back into a firm seed and 
root bed suitable for planting. 



84 CampheU's Soil Culture Primer 

CHAPTER 12 
PROPER PHYSICAL CONDITION OF THE SOIL 

By proper physical condition of the soil we mean that 
condition of tilth which will produce the best possible results. 
We wish to prove to you that on the broad level prairies of the 
semi-arid belt nature has provided all the necessary elements 
to grow cereals, vegetables, forage and fruits in such quantities 
and of such quality as to satisfy the most critical. To accom- 
plish this, however, the tiller of the soil must know what to 
do, when to do it, how to do it, and why he does it. We shall 
show you that it does not require a large expense nor a vast 
amount of labor to get good results, but it does require effort 
and intelligent knowledge with good judgment. Just as a 
valuable machine may be rendered powerless and useless by 
the wrong adjustment of a bolt or a nut, so in the mechanical 
preparation of the soil, success depends on doing the right 
thing at the right time and in the right manner. It will not 
do to guess at it. You could not put a machine together with- 
out knowing something about its parts and the principles on 
which it works. You cannot till the soil and get from it the 
best results in the nature of crops unless you know something 
of the simple principles of soil physics. 

A vast deal of misleading matter has been published on 
the subject of soil physics and its relation to soil fertility. 
Many used to think, and some think even now that a chemical 
analysis of the soil will indicate just what crops can be raised 
and the probable yield. Nothing could be farther from the 
truth. Milton Whitney, chief of the United States Bureau 
of Soils, in United States Bulletin No. 22, says there is no 
apparent relation between the chemical composition of the 
soil as determined by the methods of soil analysis in use and 
the yield of crops, but that the chief factor determining the 
yield is the physical condition of the soil. It is our candid 
opinion, based on thirty years experience and observation, 
that the farmer need not bother himself with the chemical 
analysis of his soil until he has learned to secure the proper 
physical condition to assist nature to make available and 
utilize the needed elements of soil and air. 

The potential soil fertility of the average high level 
prairie soil is all that can be desired and all that is needed is 
care in the conservation of the moisture that is applied by 
irrigation or that falls as rain and snow during the year. 

In order to secure a condition to best conserve this moisture 



Campbell's Soil Culture Primer 85 

the greatest care should be exercised in plowing, packing, and 
cultivating this soil when it is moist. When the soil is moist, 
as all observing farmers know, the soil grains separate readily, 
the soil crumbling in a mellow mass behind the plow or under 
the harrow. The real object of plowing is not to merely 
turn the soil over, but to pulverize it, and the more thoroughly 
this is done the better opportunity there is for the air and 
heat to exercise their full power in the liberation of plant food. 

Nothing influences the water-holding capacity of the soil 
more than its physical condition. The deeper the soil is stirred 
and yet made fine and firm, the greater will be its capacity 
to receive and retain moisture. To plow deep and leave the 
under surface loose and lumpy is no insurance against drouth 
and our experience has shown that we never can tell when 
a dry spell will come. 

Some would-be authorities, speaking from theory only, 
insist that our western soils must be loosened up deeply to let 
the water down. This is not essential providing the soil is 
moist a foot or so below the surface, and the surface is kept 
loose. As soon as the water comes in contact with the moist 
earth below it readily percolates down into the subsoil, 
gradually moistening it to a depth of from six to ten feet, 
depending on the amount of rainfall. In fact the soil that is 
moist down several feet will dry off more quickly at the surface 
than will a soil dry beneath. The reason is found in the more 
rapid percolation caused by the moist subsoil. 

Amount of Water Content 

A saturated soil will hold from twenty to thirty-two 
pounds to a cubic foot, depending on the kind and texture. 
The amount of this water content is least in sandy soils, 
large in loams, and reaches its maximum in soils with a high 
per cent of humus or organic matter. 

Ordinary field and garden plants will not grow in a 
saturated soil, because under this condition practically all the 
air is excluded and the roots of plants must have air. The 
ideal soil condition is to be found when all gravitational water 
has been drained off, leaving only the capillary and hygroscopic 
moisture. 

It is impossible to tell just what proportion of water 
gives the best results. It depends on the texture of the soil 
and the degree of tilth that is maintained. Intelligent observa- 
tion and practice are the only means by which a farmer may 
know when he has obtained an ideal condition of the soil as to 
moisture. 



86 Camphell's Soil Culture Primer 

CHAPTER 13 
THE DISK HARROW ITS USE AND ABUSE 

No agricultural implement is more important to the 
western farmer than the disk harrow. Its use, however, has 
been more or less misunderstood — many have tried to make 
it do the work of the plow. Thousands of acres of wheat 
have been put in with the disk alone that have not turned the 
farmer a profit of a cent, and in many cases they have not 
recovered their seed. The great value of the disk harrow lies 
in its adaptability to the work of moisture conservation, the 
preparation of the soil for the encouragement of rapid percola- 
tion of the rain water, and the pulverizing of cloddy fields, 
thus securing a better physical condition of the soil. It has 
often been used in the place of the plow when it should have 
preceded the plow. 

In handling a field for summer tillage, considering the 
cost of labor and results obtained, there is no tool that can 
take the place of the disk harrow. And while it is a tool that 
cannot be continuously employed by the orchardist, yet we 
do not see how a man can successfully handle an orchard 
without it. In combination with the plow in the preparation 
of a field for a crop the disk is most valuable — its action as a 
pulverizer both before and after the plow is complete. 

To Be Used in the Spring and Fall 

We most earnestly advise the use of the disk on previously 
cropped land as early in the spring as possible. No time 
should be lost after the soil has become sufficiently thawed 
and dry enough so that it will not stick to the disks. It is best 
to double disk by lapping one-half, the object being to break 
the surface to prevent evaporation and to present a rough 
surface to absorb the spring rains. 

It is equally as important to use the disk in the fall as 
soon as the small grain or any other crop has been removed. 
It is advised whenever possible to follow the binder with a disk 
and not allow the soil to be exposed a single day to the rays 
of the sun after the crop is removed. It is difficult to em- 
phasize the importance of this work sufficiently to impress the 
reader with its importance. Note the following reasons: 

First: There is no time in the year when water held in 
the soil near the surface will bring about such satisfactory 
chemical changes by bacterial action as during the months of 
July, August and September. This bacterial action means 



Campbell's Soil Culture Primer 87 

additional plant food for the next crop, but it will not take 
place unless the soil is moist and in a favorable mechanical 
condition. 

Second: If there is any moisture in the subsoil, if a good 
mulch is prepared to prevent surface evaporation the moisture 
from below will rise and accumulate in the firm soil just below 
the mulch, so that if no more rains come and you want to 
begin your fall plowing your ground is in an ideal condition 
by reason of the accumulated moisture beneath the mulch. 

Third : If you do not wish to plow in the fall this moisture 
can be carried over until spring, when if the season happens 
to be dry your soil can be plowed and planted and your seed 
will immediately germinate and grow while your neighbor 
who has neglected to disk his fields is worrying about dry 
weather. 

Fourth: In case you wish to sow fall wheat this early 
disl^ing, by holding the moisture as shown above, may mean 
from ten to twenty bushels additional yield per acre. If, 
after disking, a heavy rain should come sufficient to pack the 
surface, the harrow should be immediately used to break the 
crust and loosen the surface, then by following the plow with 
the subsurface packer and the packer with an Acme harrow, 
you will have a fine, firm, moist seed bed, and your wheat will 
come up, stool, and grow rapidly. 

Fifth : In m.ost of our fields, especially those sown to 
small grain, are more or less weeds. These ripen and scatter 
their seeds ready for next year's growth. Fall disking covers 
these seeds and any scattered grain, causing them to germinate 
and grow to be killed by frost or subsequent harrowings. 
Disking after the crop is removed is one of the very best 
methods for eradicating weeds. 

Size of the Disk 

When the disk harrow first came into use fourteen inches 
was the common size, and this size we still prefer but the 
farmer, conceiving the idea that a larger disk is of lighter 
draft, has been demanding a larger disk. While it is doubtless 
true that the larger the disk the lighter the draft, it is also 
true that the smaller the disk the better the pulverizing 
action. The pulverizing effect of a sixteen inch disk is not as 
good as a fourteen inch, an eighteen inch is still worse, and a 
twenty inch disk we would not have on a farm. We have 
noticed twenty inch disks rolling over ground that was some- 
what dry, slicing the soil and raising it up a little and then 
letting it fall back in large clods in practically the same position 



88 



Campbell's Soil Culture Primer 



it was in before the disk passed over it. The process simply 
made little crevices in the surface crust and actually increased 
the evaporation instead of decreasing it. A fourteen inch disk 
moving at the same rate would revolve faster, pulverize the 
surface, and completely reverse the soil. Don't buy a large 
disk, and get one with guard wheels to regulate the depth of 
cut. Double disk by lapping one-half. If you drive so that 
the side disk will just fill the furrows left by the center you 
will leave your field level. Keep your disks sharp and use as 
wide a disk as you have the power to draw — the more ground 
you can cover with one man the better. 




Campbell's Soil Culture Primer 



89 










90 Campbell's Soil CiiUure Prhner 

CHAPTER 14 
SAVING WATER BY CULTIVATION 

There are two vital points in regard to the successful 
growing of crops in the western country. The first is the im- 
portance of getting all the water possible into the ground, 
and, second, using every possible means to conserve or retain 
it there. 

The importance of a little additional water is shown by 
the effect of snowdrifts that may form on the field from any 
cause. The increased amount of moisture that seems to find 
its way into the soil when the snow melts invariably makes 
itself apparent in the growing crop as soon as a dry period 
begins to affect the crop in the least. At these points the crop 
always holds out longer, sometimes carrying the crop over 
to another good rain, which results in maturing an unusually 
large yield on these places, while the balance of the field will 
not yield to exceed one-half or one-fourth the amount. Thus 
a gain in yield of wheat of probably ten bushels to the acre is 
the result of perhaps not over an inch of additional water 
that had percolated into the ground. The enormous evapora- 
tion from our fields under favorable conditions is not in the 
least comprehended by the average farmer because he has 
no means of readily testing and proving. 

To be successful the farmer must grasp the full import- 
ance of doing all his work just at a time when the condition of 
the soil is best adapted. The idea that by plowing today we 
may get ten bushels of wheat to the acre, when if we plowed 
the ground four days later we would get fifteen bushels, or 
vice versa, seems rather ridiculous. "While this statement ar.d 
the figures used may be a little strong, yet it is a fact that 
the average yield of a field is frequently increased or decreased 
quite a percent by a few days variation in the tim.e the work 
is done. This is especially true with reference to cultivation. 
We have in mind a case near Fairmont, Nebraska, where the 
phenomenal difference of fifteen to eighteen bushels per acre 
was made by cultivating a part of the field before a heavy 
rain of nearly five inches and the balance of it after this rain. 
The reason of this remarkable difference was simply what we 
have been dwelling upon, the result of retaining a large per- 
cent of moisture by the soil mulch produced by the cultivation 
after the rain, that was lost from the balance of the field by 
rapid evaporation. This occurred in July, and was the last 



Campbell's Soil Culture Primer 91 

cultivation preparatory to what is called "laying by" the corn. 
The rain was a very heavy one. 

The part of the field that was cultivated previous to the 
rain was left with the thick compacted crust made by the 
heavy fall of water, which resulted in dissolving the loosened 
soil and settling it very close, thus leaving the surface in the 
best possible condition for a rapid movement of moisture to 
the surface and evaporation. The portion not cultivated 
previous to the rain was gone over as soon after the rain as 
conditions would permit, thus producing a perfect protection 
to the moisture below, and bringing about the remarkable 
result referred to. While these cases cited seem extreme 
under similar circumstances you can look for similar results. 
When the reader begins to understand the direct effect of 
these conditions it will then be quite clear why a light crop 
was secured when a good crop might have been harvested. 

Getting Water Down Into the Soil 

The problem of getting the water down into the soil is 
one of equal im.portance with that of conserving the moisture, 
which is now quite commonly understood and accomplished 
by the use of the soil mulch or surface cultivation. In Figure 21 
we have attempted to illustrate the percolation of water, or 
the getting of water down into the soil. W^e have divided this 
figure into three sections, numbering them 1, 2, and 3, from 
left to right, then dividing these sections into lateral strata 
A, B, C, and D. In section No. 1, A represents the soil mulch, 
a stratum of light, loose, and dry soil; B represents a stratum 
of thoroughly pulverized and firm soil, m.eaning the portion 
that is cut by the plow; C represents about eight inches of 
the subsoil into which water has percolated; and D represents 
the portion of subsoil still below that is yet dry. In section 2 
we find the mulch has been compacted by a heavy fall of rain. 
This mulch in its loose condition takes in the water, and as 
soon as the water reaches the moist soil found in strata B 
and C, it immediately percolates down below, and is shown 
by the darker portion of soil in the upper part of stratum D. 
Here the water has come in contact with dry soil, which 
resists percolation. Slowly and steadily by gravity the water 
finds its way down the columns of soil, which by the way, 
throughout the entire semi-arid belt, are almost invariably 
found in a perpendicular position. In section 3 we have 
again reproduced the soil mulch by cultivation to stop the 
evaporation or loss of water from thej surface, and we find 
the moisture below has percolated on down until the water is 



92 



CampheU's Soil Culture Primer 



all distributed, each little particle taking on its film of water 
to a given thickness which it seems to steadily hold onto while 
the balance of the free water finds its way on down until it is 
all distributed. The next rain will result the same as is shown 
in section 2, only we have six, eight, or twelve inches more 
moist soil for it to pass through before reaching the dry soil. 

Effect of a Moist Soil 

An illustration will make this more clear. In setting out 
our cabbage or tomato plants in the spring of the year when 
the surface is dry and fine, we usually water them. In our 




12 3 

Fig. XXI 

Showing Effect of Percolation of Soil Moisture 



first application of water to this dry surface we notice the 
water does not seem to percolate, but for a little time remains 
dormant on the surface. After a little it finds its way down 
through the dry particles by force of gravity, leaving each 
particle it passes covered with a thin film of water. Then we 
apply a second application of water while the surface is still 
moist and we notice the water immediately disappears. The 
reason of non-percolation of the first application is because 
of the resistance of the dry particles to moisture, or repulsion 
for water. The quick movement of the second application of 



Campbell's Soil Culture Primer 93 

water into the ground is the result of the attraction of water 
for water. 

This illustrates how easy it is to get moisture into the 
soil by keeping the surface constantly loose and open, so that 
as the rain falls it soon works its way through the larger 
pores until it reaches the moist particles in the firm soil when 
it immediately percolates on down below. Here again nature 
has done a great deal for the semi-arid belt. The peculiar 
formation and size of the usual particle of soil is very favorable 
for percolation; also for its return upward by capillary attrac- 
tion to feed the plant during our long dry seasons. The move- 
ment of this moisture upwards cannot be better illustrated 
than by the movement of the oil up the lamp wick. No 
matter how deep the bowl of the lamp is, if the wick reaches 
the bottom the blaze continues to burn, not only until the oil 
is all taken from the lamp but until the wick has become quite 
dry. The same rule or fact applies to the growing plant. So 
long as there is plenty of moisture below it will move up 
through the soil to the plant, keeping it in a perfectly healthy 
condition until the moisture is not only exhausted for several 
feet down, but the soil near the plant has become apparently 
quite dry. Then the plant begins to fade and wither. 

The deeper you can store the moisture the greater are 
your chances of securing a large crop. 

A piece of ground that is moist for two or three feet down 
will take in the water of a heavy rain much quicker than 
ground that is dry. Here again is illustrated what moisture 
will do for us when we understand its ways. 




mtm^ 



ANCIENT SAXON I'LOW. 



94 CampbeWs Soil Culture Primer 

CHAPTER 15 

CORN 
Preparation of the Soil 

In the eastern states, among the hills of New York and 
New England, a large amount of time is given to the prepara- 
tion of the soil. Experience has taught them that without 
this, crops are light. Barnyard manure is used freely, and 
two, three, or four dollars worth of fertilizing per acre is not 
uncommonly necessary in order to secure good crops. Professor 
Bailey of Cornell University, Ithaca, New York, has well 
said that no after cultivation can make amends for a poor job 
of preparation. This applies just as much to the semi-arid 
belt as it does to the eastern sections of the country. In 
Illinois the soil is more fertile and rain usually ample, so that 
no fertilizers are required and when the rains are ample and 
timely two or three ordinary cultivations produce a good 
crop of corn. But even there they are beginning to learn the 
value of conserving the water by more frequent cultivation, 
because of dry periods that are liable to come at any time. 
In the semi-arid belt more attention must be given to the 
preparation of the ground. We cannot depend upon heavy 
rains to aid us in dissolving and settling our soil, consequently 
we must give close attention to every part of the work. The 
first thing in order is the early disking which should be a 
double disking in order to thoroughly pulverize the surface, 
bearing in mind that every act must be to store and provide 
the greatest possible amount of water in the soil. Early 
disking covers the two important points previously referred 
to, that of preventing the evaporation and opening up the 
surface to receive the later rains. This done, we simply wait 
for the proper time of further preparation and planting, 
always being in readiness, however, to loosen the surface at 
any time should we get a rain of any magnitude. There is 
some diversity of opinion as to whether the check-rower or 
lister is preferable, more particularly in the lower altitudes. 
We favor the lister in the higher altitudes, or in the northern 
sections where the nights are cooler which results in heavier 
stooling or suckering. These additional shoots are very 
detrimental to the corn crop, especially so should we have a 
dry season, but for the more humid sections we still favor 
the check-row planting especially on rolling land. 



Campbell's Soil Culture Primer 



95 



The Lister 

The lister has one advantage that is especially desirable. 
By filling the furrows about the time the suckers begin to 
show they are covered up completely. Another advantage is 
that of getting the roots deeper into the ground. The higher 
the altitude and the drier the atmosphere, the deeper is it 
necessary to cultivate in order to produce a deeper mulch to 
prevent evaporation. In using the lister on ground where 
the moisture has been carefully preserved by disking and 
harrowing in the early spring it is quite important to follow 
the lister with some tool to thoroughly pulverize the moist 
soil that is thrown up as such soil soon becomes dry and very 
hard and is afterwards hard to manage. 




iBk 



WBmmmmlilm . 



Fig. XXII 

Corn Planted With a Lister 



The best tool for this purpose is the weeder; the long 
flexible teeth lap down on the side of the furrow or ridge as 
thrown up between the rows and quite completely pulverize 
the large clods that are thrown up by the lister, leaving a 
perfect circle with a nice fine mulch over the entire surface. 
This puts your ground in magnificent shape, especially in the 
sand loam soils of the semi-arid belt, so that you can continue 
the use of the weeder by going lengthways of the ridges and 
completely destroving the weeds before they assume any size. 
Keep your mulch'in perfect condition to prevent evaporation 
by going over the ground after each rain as in the cultivation 



96 CampheU's Soil Culture Primer 

of other crops, watching the condition very closely in order 
that you may catch the ground just when slightly moist, 
before the crust has begun to form. This does away with the 
weed cutting idea. 

In growing listed corn we do not believe in very deep 
listing, but in thorough cultivation from early spring until the 
crop is put in, then consider fully that ample moisture and air 
must be in the soil and that weeds growing in a corn field live 
on your best corn. 

Check Row Planting 

In planting with the check row planter it is important to 
plow the ground as early as possible. Here, again, the early 
disking comes in with its all important results to prevent the 
evaporation, holding your ground in perfect condition for 
rapid percolation of the later rains. This is advisable because 
you can get onto your ground with the disk when it would be 
too wet at a proper depth to plow. Then, again, you can 
cover the field quicker if you have a broad gauged disk than 
with the plow. It also enables you to get your soil in much 
better physical condition than would be possible if the ground 
were allowed to dry out. The plowing should be followed 
up soon after, but remember this point — if you have been 
particularly persistent in preventing this evaporation by the 
disking, your ground is in perfect condition to plow, even 
though you have considerable dry weather later on in the 
spring. The soil will roll up in a moist condition, and is 
susceptible to the best results with the packer or any other 
tool. Follow the plow closely with the packer, at least every 
noon and night. 

There are few places where the subsurface packer turns 
the profit it will in following the plow in preparing a field for 
corn. In an experiment on the Burlington farm in Phelps 
county, Nebraska, in 1904, where a strip of land in a field 
being prepared for corn was left without packing, the following 
facts were observed: Germination was four or five days 
slower; the stand of corn much less uniform and the final 
yield per acre fully fifteen bushels less. 

After your ground is turned over and the necessary work 
done to pulverize the surface, watch closely the condition. 
Whenever any rain comes, even though it only wets through 
the mulch or loose soil on top, it is necessary to immediately 
stir it to dry it out. 

The growth of roots as shown under the head of root 
development is also interesting. Do not put in too much 



Campbell's Soil Culture Primer 



97 



seed. There are unquestionably many instances where very 
Hght crops of corn have been secured from too much seed. 
Had there been half as many stalks growing there would 
have probably been two or three times as much corn. We 
have frequently heard the remark: "If you don't put in the 
seed you can't get the crop," indicating the crop was gauged 
by the quantity of seed. This is another mistake and is 
beginning to be more generally understood. The strongest 
evidence along this line is found in some experimental work 
which we conducted in 1897, where eight ears of corn were 




Fig. XXIII 

Showing the Extensive Root Development of a Hill of Corn 

raised I from one single kernel. Seven of these were well 
developed [ears, the eighth having corn about half the length 
of the cob, the upper and lower ends being bare of corn. 
Amount of Seed Necessary 

One fact not generally known is that every healthy corn 
stalk starts from five to ten ears. Now the development 
of these ears depends entirely upon the physical condition of 
the soil and the supply of available soil moisture, air, and 
plant food. It is true there are conditions that might exist 
where more corn might possibly be got from two, three, or 
four stalks in a hill than one. There would be rare cases 



98 Campbell's Soil Culture Primer 

where by extreme heat the demands upon the supply of 
moisture and plant food might suddenly destroy the vitality 
of all the ears that were started on the corn except the top one; 
then a sudden and liberal rain replenishing the soil about the 
roots with the necessary moisture would immediately increase 
the supply of plant food and push to completion the single 
ears left on each stalk, when we would have two, three, or 
four ears to the hill as against one ear if we had but one stalk. 
But should the dry period continue longer without any 
rain we might lose all the ears because the demand for 
moisture to supply the growth and development of two, three, 
or four stalks would be just that much greater than for one 
stalk, consequently the one stalk could endure the drouth 
longer without suffering, and probably reach the next rain 
when ample moisture would mature one or two good ears, as 
against none at all with a larger number of stalks. 



Things to Remember: 

Plenty of water in the soil makes plenty of corn. 

No after cultivation can make amends for a poor job of 
preparing the soil for a crop. 

The deeper you can get the water stored down in the 
ground before planting time the surer you are to get a big 
crop. 

Cultivate your corn at least once after the last rain. 
If you don't need the water for this crop you may the next. 

Don't get the shallow idea too strongly fixed. Two and 
a half to three inches of fine loose soil is about the best con- 
dition. 

Watch the first approach of spring and as soon as you can 
get into the field with your disk, go over your ground intended 
for corn. Nothing can pay better. 

There is no work done, cost considered, that seems to 
go farther toward increasing the yield of corn than that of 
early double-disking. This is also quite true with reference 
to all other crops. 

Never allow a crust to form under the mulch any more 
than you would on the surface. It will get there if you don't 
watch closely during times of extreme heat in long dry periods. 
Don't let weeds grow. Every weed means less corn. 



Campbell's Soil Culture Primer 99 

CHAPTER 16 

WHEAT 
Spring Wheat 

In discussing the growing of wheat it seems almost neces- 
sary to divide it into two headings — winter and spring. 

Spring wheat in the northern sections and in Canada has 
become a very important crop. In preparing ground for this 
crop Uttle attention has been given in the past to the all 
important question of storing and conserving the rain water. 
It has been simply a question of plowing at any time when 
the farmer was ready to plow, the seeding and harrowing 
likewise, without reference to the condition of the soil or the 
storage of water. In the more arid portions of the wheat 
belt in the northwest there is no question that summer tillage, 
commonly termed summer fallow, would be found exceedingly 
profitable. While we have thoroughly discussed this question 
in another chapter referring especially to summer tillage, yet 
its work is of such great importance and the additional expense 
so little compared to results that we cannot resist a repetition. 

If the work is properly done the returns are large. Begin 
first in the early spring, just as soon as the frost is out of the 
ground and the soil sufficiently dry to permit of disking with- 
out the soil adhering to the disk; lap half so as to thoroughly 
pulverize the surface, thus putting your ground in condition 
to prevent evaporation, as well as to admit of the rapid percola- 
tion of the early rains and you will be surprised at results. 
Keep the surface harrowed or loosened by the use of some 
tool to the depth of at least two inches, plowing in June or 
July, the time when other work is least pressing, to a depth 
of six or seven inches, following the plow closely with the 
subsurface packer and let the packer be followed closely with 
the harrow, keeping in mind that all-important point of work- 
ing the soil when it is in the best condition to most thoroughly 
pulverize, continuing this surface cultivation after the plowing 
through the entire season. In this work again the Acme 
harrow is most desirable because each time over it brings the 
soil from below up and to a large extent turns the soil from the 
extreme surface to the bottom of the portion stirred by the 
Acme. In this kind of work in the northwest, as well as in 
any portion of the semi-arid belt, it is very important to do 
this surface cultivating, whether it be with the common 
harrow or the Acme harrow, spring tooth or disk, at a time 
when the soil is in the best possible condition; that is, simply 
moist, not dry or wet. Then you have a fine, even soil mulch 



100 Campbell's Soil Culture Primer 

composed of minute lumps, a condition you cannot get if the 
soil is dry or wet. It is when soil is in this condition that the 
particles seem most readily to separate, not simply into dust, 
but into minute lumps made from slightly moist soil which 
when dry will never blow. 

Having had twenty-five years experience in the northwest 
I am well aware of this blowing difficulty on the lighter soils, 
which can be entirely prevented by care with reference to the 
condition of the soil as above stated. It is very desirable in 
following this plan to keep the weeds entirely clean from the 
field. Don't for a moment encourage the idea that weeds are 
valuable to turn under, for there is so little value to them 
that it is not worthy of consideration, but the water drawn 
out of the soil by these weeds while growing is far more valuable 
to the coming crop. Watch it carefully. In the springtime 
try to catch this ground as early as possible with the harrow. 
Acme preferred, and put in your seed, not to exceed one-half 
bushel to the acre. This quantity is ample. 

If you will give close attention to this point you will 
simply be astonished at the results obtained. When a crop 
has been taken off, get on this ground as quickly as possible 
with the disk harrow. Double disking is exceedingly valuable. 
The small size disk, fourteen or fifteen inch, set at a good 
angle will quite thoroughly pulverize the ground, but with 
the larger disk it is impossible to get a good condition without 
double disking. Remember that the object is to thoroughly 
pulverize the surface two or three inches, to not only prevent 
the loss of any moisture we may have below, but to have the 
ground in the best possible condition on the surface for the 
rapid percolation, or getting of the rain waters down into the 
soil. Lose no time after any rain in again loosening the surface, 
especially upon ground that you may have already plowed. 
After the disking, plow and pack and harrow, as stated with 
reference to summer tillage. Should you get any heavy 
rains late in the fall lose no time in loosening the surface to 
save the water, for you may need it the following year. 

When spring time comes get over your ground as quickly 
as possible with the harrow, aiming to do this before 
the surface gets dry, put in your seed, not too thick, 
and await its development when it reaches the stooling point 
which it will do early in the season if your ground is in condi- 
tion. At this point of growth, that is when the wheat is 
beginning to stool, or tiller, go over your ground with a long- 
toothed weeder. This will loosen the surface and destroy the 
weeds. The checking of evaporation by this cultivation will 



CamphelVs Soil Culture Primer 101 

urge on your wheat when it will soon cover the ground, then 
the danger of evaporation is much less. The rich prairie 
soils of the Dakotas, Minnesota, and other sections of the 
northwest should produce thirty to forty bushels of spring 
wheat instead of five to twenty, and will if the soil is properly 
handled. 

Don't think that you can get this rapid growth and early 
heavy stooling of the wheat unless your ground is thoroughly 
fined and firmed and you have held the moisture below, form- 
ing a seed bed in which there will be a rapid development of 
strong roots which is the direct result of prolific stooling. The 
use of the weeder, or harrow, on wheat after it has begun to 
stool, or is three or four inches high, when your ground is 
loose and porous where the roots should grow, is not always a 
safe proposition. The root development is so light that much 
of the wheat may be easily pulled up and destroyed. 

Winter Wheat 

Winter wheat is a little different proposition from the 
spring wheat. Here again we believe when the farmer in the 
winter wheat belt has learned the value of summer culture 
and how it will not only greatly increase the average yield, 
but make a failure, so far as drouth is concerned, an im- 
possibility, a large acreage will be thus treated. Our experience 
and the experience of thousands of others during the last 
twenty years is certainly evidence that our ideas drawn from 
years of experience and observation are something more than 
theory. They at least carry very strong evidence as to the 
value of this class of work where by thorough and careful 
preparing of the soil, having plowed about seven inches 
deep, following our plow closely with the subsurface packer, 
and the packer with the Acme harrow, going over our 
fields immediately after the heavy rains, or as soon as the 
soil was sufficiently dry to permit it, we had formed a fine, 
firm and very moist seed bed. Under these conditions twelve 
quarts of seed was found to be ample. Its germination was 
quick and the rapid development of roots brought about by 
the very favorable physical condition of the soil caused 
liberal stooling and in thirty days after seeding the ground 
was nearly or quite covered with the wheat. 

Disking after the Binder 

The immediate disking after the winter wheat crop is 
removed is of very great importance; as we have repeatedly 
said, it is of two-fold value as it prevents the loss by evapora- 



102 Campbell's Soil Culture Primer 

tion of moisture in the soil and puts the surface in the 
best possible condition for the rapid percolation of later rain 
waters. The plowing may be done a little later, and to get 
the best results a good depth of plowing is necessary, and 
then the plow should be followed with the subsurface packer. 
Mark you, we are after a condition that will not only enable 
us to get the best possible results, but prevent the serious 
damage by drouth and assure good crops annually. A fine, 
firm seed bed, or root bed, has many advantages over the 
coarse, loose one. 

In the first place, only one-third of the seed usually sown 
is necessary. In the next place, the growth and development of 
the plant is much more rapid and will soon cover the surface. 
In the third place, the development of roots is much greater, 
we are able to draw moisture and plant food from a much 
larger percentage of the soil, and, last but not least, we have 
a condition of soil that will hold a much greater percent of 
moisture as well as one having a greater power of capillary 
attraction, enabling us to keep up the supply of moisture 
which we draw from below, where by careful work, much of 
the rain waters are stored that under ordinary conditions 
would have been lost by evaporation or run-oflf. 

The plan of raising wheat by plowing every third or fourth 
year and simply using the disk for two or three consecutive 
years, or even reducing the cost still further of putting in the 
crop by using a disk drill, is altogether wrong. It is not at all 
surprising that many farmers resort to this instead of simply 
plowing three or four inches deep, leaving the plowing without 
even harrowing, lying up light and loose and full of cavities, 
a condition that could scarcely produce anything but weeds in 
an ordinarily dry season; yet it seems like folly for a man to 
so prepare his ground that nothing but a very favorable 
season could give him even a fair crop, when with a little 
additional work he is able to materially increase the yield 
as well as guard against a failure. No farmer should be 
content to call twenty bushels of wheat a good crop. Our 
prairies of the semi-arid belt are capable of producing forty 
and fifty bushels with the conditions nature has provided. 



Campbell's Soil Culture Primer 103 

CHAPTER 17 
IRRIGATION 

Economical Use of Water 

It would hardly be proper to close this book without a 
word on irrigation, especially considering the fact that some 
seem to have the idea that the Campbell system is an- 
tagonistic to irrigation and that the promotion of this work 
generally would retard the development of irrigation enter- 
prises, but this is far from the truth. We have millions of 
acres of the most fertile lands, level and easy of cultivation, 
that can never be irrigated without unwarranted expense, 
which receive ample rainfall annually to produce fine and 
profitable crops if these waters are properly stored and utilized. 
Then there are millions more of choice acres with sufficient 
rainfall to make irrigation impracticable where the present 
average yield is not to exceed one-third what it might be if 
the general principles outlined in this book were fully 
understood and practiced by the farmer. 

Then again we have millions of acres for which irrigation 
is necessary to secure profitable returns, but the available 
water is not sufficient when so wastefuUy used as is 
the case today along most of our ditches. Most men seem to 
think when they have the ditch completed, and water in un- 
limited quantities, they are in position to grow large crops. 
They are, but do they? Not as a rule, and the only reason 
why they do not is they do not handle the soil correctly. 
The average farmer in Illinois, Iowa, and the other similar 
states does not obtain to exceed one-half the yield he 
might from his fields were he more familiar with the scientific 
principles of soil culture; or, in other words, if he better 
understood the relation of the soil and moisture to plant 
growth. The same can be said of the average irrigator. The 
same great and vital question arises in irrigation — the utility of 
air and water. 

Campbell System Applies 

The fundamental principle upon which the success of the 
Campbell system is based is the economical use of water, it mat- 
ters not from whence it comes, whether direct from the clouds 
or from flowing streams, ditches, reservoirs, or wells. The 
first and very important thing to do is to get a supply of water 
stored in the soil to feed, nourish, and mature the crop in a 
period of dry weather; the second and almost equally important 



104 CampheU's Soil Culture Primer 

requisite is the seed and root bed, so vital in the success of 
this system, all of which is necessary in growing crops 
by artificial application of water required by irrigation. And, 
third, but by no means least, is that very important question 
of the control and utility of air, a question very little under- 
stood and much less appreciated by the average irrigator as 
well as the average farmer generally. It is true that a man 
may get a better crop with plenty of water to turn loose at 
will upon a piece of ground poorly fitted than he could with 
the same reckless fitting and be obliged to depend upon 
replenishing his soil with moisture from the heavens, but this 
is not the question today with the progressive farmer. It is 
how can we get the greatest results from our soil, labor and 
expense. In irrigation water usually means money. There 
are few irrigation ditches today that carry enough water 
through the season to irrigate all the land that might be reached 
with water from the ditch. There are many fields that are 
made to suffer that are under the ditch and crops made light 
that if the principles involved in this book were understood 
and applied precisely as we outline them, larger yields might be 
realized, and more acres covered with the same amount of water. 
And this will be realized when the irrigator better under- 
stands the nature of plants and just what physical condition 
is best for the support of healthy roots and how they gather 
plant foods. Due consideration must be given to the roots of 
the plant and their necessary supply in proper quantities, not 
only of water, but of air also. Too much water at times is 
just as detrimental as too little water. Too much air, as well 
as too little air in the soil is also a serious hindrance to the 
growth of the plant. Only the proper quantity of both can 
bring best results. A clear conception of how water moves in 
the soil is just as important to the irrigator as to the man who 
depends solely upon the rainfall. 

The ideal condition for the most healthful and successful 
growth of all cultivated crops is a good depth of root bed made 
thoroughly fine and firm. There is little danger in getting the 
average sand loam soils so common in the arid and semi-arid 
sections too firm while some of our heavy clay soils if not 
properly handled might become too closely compacted; but 
this kind of soil is not at all common. Previous to the thor- 
ough fitting of the seed and root bed see to it that ample 
moisture is stored below where nature can do her part by 
bringing it up to the roots of the growing plants by capillary 
attraction, then keep your surface always cultivated in such 



Campbell's Soil Culture Primer 



105 



a manner as to provide as near as possible a fine, loose mulch 
of soil (not dust), stirring it often enough to keep the moisture 
up to the top of the firm soil just beneath the mulch. The 
moment the top of this firm soil becomes in the least dry there 
is immediately a process of depositing of salts and other 
matter between these particles of soil, closing the pores and 
consequently diminishing the quantity of air that should 
freely pass through this soil to the roots. This condition not 
only points to the fact that you are allowing the air to be 
shut out but that you are losing the moisture by evaporation 
from the soil. 




Fig. XXIV 

Furrow Irrigation. An Economical Method 



106 Campbell's Soil Culture Primer 

CHAPTER 18 
CROP ROTATION 

We advocate crop rotation as far as it can be carried out. 
There is an advantage in rotation in a three years plan in the 
semi-arid belt. The plan we suggest is not absolute but one 
that can be safely carried out. The same plan also may 
apply in the winter wheat section of Canada. However, with 
a rainfall that can be reasonably relied upon for time and 
quantity of twenty inches, we believe with summer tilling 
one year, cropping the next two and then summer tilling again, 
that by close observation to details in conserving moisture 
the entire year through there is little or no question of good 
crops being grown annually for a number of years, but no 
one should bank on this until he has thoroughly mastered 
the question of summer culture and the necessary physical 
condition of the soil. 
First Year 

Begin by summer tilling one season. Go at it with a will 
and see to it that you store and conserve the entire season's 
rainfall from early spring to autumn. Keep out the weeds. 
Sow your fall wheat, if in central or southern Nebraska, first 
to tenth of September; if in northern to central Kansas, sow 
from the tenth to the twentieth of September, using not over 
thirty pounds of seed. If your work has been well done and 
the soil is in good physical condition do not sow more than 
twenty pounds of seed per acre. Remember that our dates 
for seeding and quantity of seed are based on thorough prepar- 
ing, under which conditions it will be found that the fall 
growth will be ideal. 
Second Year 

The second year we harvest our wheat crop in Kansas 
in June, in Nebraska the last of June or early July, From the 
harvesting of this crop to the close of the season we prepare 
for the crop to be grown the third year as follows: 

If possible, follow the harvester with the disk. If you 
cannot do this, go over the field with the disk just as soon as 
the crop is cut. Whatever you do, double disk as elsewhere 
explained. The quicker and more thorough you do this the 
better will be your crop the following year. After double 
disking, continue just the same as if summer tilling. Keep 
the weeds down at all hazards and get over the ground with 
some tool as quickly as conditions will permit after each 
rain. Plow as soon as the soil is in condition, following all 
work after plowing the same as for summer culture and you 



Camphell's Soil Culture Primer 



107 



are ready for a crop of corn the following spring, or oats if 
you prefer, but corn is preferable, and if well tended you can 
bank on a crop. 
Two Crops in Three Years 

This plan, if faithfully and carefully carried out in sections 
similar to western Kansas and Nebraska will result in two 
good crops out of three years of a proportionate magnitude 
to the crops reported elsewhere by the every other year plan 
by summer culture one year and cropping the next. In a 
series of ten years average crops will be produced that will 
compare favorably with the average crops grown in Iowa or 
Illinois under the present general methods in the same number 
of years. 





l$V* - 


FODDKR 4 3ST) CORH 


191* - BARLEY 




'■\l: 


BWLKY 


■Ij - OATS 

'l' - ffH^s.T (SEEDED) 




OATS 




•17 - 


WHEAT (SENSED) 


*17 - GRASS 




•IS - 


CRASS 


•l3 - GRASS 




■i; - 


CRASS 


'19 - FODD"^ 4 £EKD CORN 







20 A. 


E -0 A. 




191^ - 


GRASS 


I9IU. - OATS 




'15 - 


FODDER 4 SE"rD CCRK 


15 - THEAT (SEHJED) 
■16 - GRASS 




•15 - 


BARLEY 




"17 - 


OATS 


•17 - CRASS 




•13 - 


WHEAT (SEEDED) 


•is - FODDER 4 SEED CORK 




19 - 


GRASS 


'19 - BARLEY 


c 




20 A. 


F :c A. 




191+ - 


GRASS 


I'-l-ROOTS 4 FODDER 


l^OAT HAY 




"15 - 


GRASS 


CORN 


15-FODDER CORN 4 




•i5 - 


FODDER 4 SEED CORN 


15- OAT HAY 


ROOTS 




'17 - 


BARLEY 


IS-PASTURE 


16-ROOTS 4 FODDER 




■13 - 


OATS 


17- PASTURE 


CCfiN 




■19 - 


WHEAT (SEEDED) 


13- OAT HAY 

19- FODDER CORN & 


•17- OAT HAY 
IS-PASTUHE 


B 




20 A 


ROOTS 

G 10 A. 


19-PASTURE 
I 10 A. 




















':!^- PASTURE 




191"* - 

'11: 


WHEAT (SEEDED) 

GRASS 

GRASS 




Li'ARnS- 


'13- PASTURE 
'16- OAT HAY 
17- FODDER CCRN 4 


EZj :~'I 


HUUST 




'.17 - 


FODDER 4 SEED CORN 


-w 


ROOTS 
'iS-ROOTS 4 FODDER 

CORN 
19- OAT HAY 




IS - 

1^ - 


BARLEY 
OATS. 


3^ HOUSE! j i 


JO 


GARDEN: 


A 




cO A. 


Q^ARDEN 


1 
1 


H :o A. 



Fig. XXV 
A Well Arranged Farm Showing a Six Year Rotation 



108 Campbell's Soil Culture Primer 

CHAPTER 19 

NECESSARY FARM TOOLS 

We have been asked many times for a list of the implements 
we consider best adapted to general farming on the prairies 
of the great semi-arid belt. This, we realize, is a delicate 
subject on which to give advice, therefore we simply give a 
list of such tools as we bought for our own farms. For ordinary 
sized farms we favor four horse tools, or larger, as far as it 
is possible, for to decrease the cost of production adds profit. 
When one man can turn over two fourteen-inch furrows or 
twenty-eight inches by driving four horses instead of sixteen 
inches by driving three horses, he is not only decreasing the 
cost of plowing over thirty percent, but is getting a field 
plowed in six days that would take ten days with the sixteen 
inch plow. This is an advantage in many ways, and what is 
true of plowing is proportionately true of all other farm work. 

The following tools make a very complete outfit for four 
good heavy work horses and with these horses and tools 
80 to 100 acres can be handled on the high level prairies of the 
semi-arid belt where the soils are of the usual sand-loam 
formation. 

List of Tools 

One gang plow, two fourteen-inch bottoms. 

One four horse disk harrow. 

One four horse Acme harrow. 

One spike-toothed harrow. 

One four horse subsurface packer. 

One two row cultivator. 

One one horse cultivator. 

One Eureka weeder and mulcher. 
In addition to these tools come such planters, drills and 
harvesters as shall be needed for the crops the farmer may 
wish to raise. 

The list of tools is such as has been found most desirable 
for securing the best possible physical conditions of the soil 
at the least expense. 

There is no tool among these mentioned when it comes 
to farming in the semi-arid belt under conditions where a dry 
period is liable to come at any time during the growth of the 
plant, that will do as much to increase the yield and certainty of 
crops as the subsurface packer. 



"""■" " ' —<•—•• "-— " <• " .J^ 

CAMPBELL'S 

Soil Culture Manual 



The development of scientific agriculture 
during the last five years has raised farming 
to a profession and reduced the best practice 
to a system. The Campbell methods, as out- 
lined by the first publications of Mr. Campbell, 
have been enlarged and perfected into a logical 
and practical system of soil tillage and the 
conservation of soil moisture, applicable not 
only to the semi-arid regions of the world, 
but to every condition of climate and rainfall. 
In fact, the Campbell system is the only log- 
ical system of scientific agriculture yet given 
to the public. There are various books and 
bulletins published on the different phases 
of agricultural science, valuable books, but 
as yet no other correlated system of practice 
has been given to the world. 

The principles, practice, progress and history 
of the Campbell system, both in this country 
and abroad, have been compiled and will be 
published this year as Campbell's Soil Culture 
Manual, 1914 edition. It will appear in one 
large volume of over 500 pages, fully illustrated, 
and will contain the last word on scientific 
soil culture, as applied to the growing of 
various crops. 



The work has been arranged and edited by 
RICHARD A. HASTE, Editor-in-chief of 
CAMPBELL'S SCIENTIFIC FARMER and 
editor of the SCIENTIFIC SOIL CULTURE 
SERIES. 

^ X; 



Agricultural Education 

This is an age of efficiency — of education for efficiency. 
A man to be successful must be an expert in his line. And 
this is becoming true of the farmer. Agricultural education 
is in the air — you hear it everywhere. Nearly every state in 
the Union has a law providing for agricultural education in 
the public schools. But what are we going to do with this 
generation — the generation that is past school age? Where 
can the farmer who wants more definite knowledge about his 
work get this information? Where can the man who wants to 
be a farmer get a working knowledge of this newest profession? 
These are vital questions that must be answered. They have 
not the time to go to the agricultural colleges — that is out of 
the question. The agricultural college must come to them. 
That is just where 

The Campbell Correspondence 
School of Soil Culture 

comes in and fills a keenly felt want. This great school fur- 
nishes the only reliable instruction in the science of agriculture 
outside of the agricultural colleges, and you don't have to 
leave home to get it. 

You have your choice of the following courses: 

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Soil Tillage Course 

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